feat: 添加 PLC 串口自动搜索

app/integrated_platform.pro

@@ -48,11 +48,13 @@ SOURCES += \
     src/services/software_logic_executor.cpp \
     src/services/offline_simulation_service.cpp \
     src/services/runtime_mode_service.cpp \
+    src/services/plc_discovery_gateway.cpp \
     src/services/register_monitor_service.cpp \
     src/services/register_comment_service.cpp \
     src/infrastructure/plc_register_repository.cpp \
     src/infrastructure/plc_communication_error_classifier.cpp \
     src/infrastructure/plc_communication_service.cpp \
+    src/infrastructure/plc_discovery_service.cpp \
     src/infrastructure/json_project_storage.cpp \
     src/ui/hmi_editor_widget.cpp \
     src/ui/logic_editor_widget.cpp
@@ -94,12 +96,14 @@ HEADERS += \
     src/services/software_logic_executor.h \
     src/services/offline_simulation_service.h \
     src/services/runtime_mode_service.h \
+    src/services/plc_discovery_gateway.h \
     src/services/register_monitor_service.h \
     src/services/register_comment_service.h \
     src/services/plc_communication_gateway.h \
     src/infrastructure/plc_register_repository.h \
     src/infrastructure/plc_communication_error_classifier.h \
     src/infrastructure/plc_communication_service.h \
+    src/infrastructure/plc_discovery_service.h \
     src/infrastructure/json_project_storage.h \
     src/ui/hmi_editor_widget.h \
     src/ui/logic_editor_widget.h

app/src/infrastructure/plc_discovery_service.cpp

@@ -0,0 +1,304 @@
+#include "plc_discovery_service.h"
+
+#include <QModbusDataUnit>
+#include <QModbusPdu>
+#include <QModbusReply>
+#include <QModbusRtuSerialMaster>
+#include <QSerialPort>
+#include <QSerialPortInfo>
+#include <QTimer>
+#include <QVariant>
+
+#include <string>
+#include <utility>
+
+namespace {
+
+// 本地 RTU 探测无需沿用正式轮询的长超时和重试，否则多端口搜索会过慢
+constexpr int kDiscoveryResponseTimeoutMs = 200;
+// 正式连接可能刚被配置窗口断开，先留出时间让操作系统完全释放串口句柄
+constexpr int kDiscoveryStartDelayMs = 100;
+
+std::string toUtf8(const QString &value)
+{
+    const QByteArray bytes = value.toUtf8();
+    return std::string(bytes.constData(), static_cast<std::size_t>(bytes.size()));
+}
+
+} // namespace
+
+PlcDiscoveryService::PlcDiscoveryService(QObject *parent)
+    : QObject(parent),
+      master_(std::make_unique<QModbusRtuSerialMaster>())
+{
+    connect(
+        master_.get(), &QModbusClient::stateChanged,
+        this, &PlcDiscoveryService::handleDeviceStateChanged);
+}
+
+PlcDiscoveryService::~PlcDiscoveryService()
+{
+    progress_changed_callback_ = {};
+    discovery_finished_callback_ = {};
+    if (master_->state() != QModbusDevice::UnconnectedState)
+    {
+        master_->disconnectDevice();
+    }
+}
+
+PlcCommunicationResult PlcDiscoveryService::startDiscovery(
+    const PlcSerialConfiguration &preferred)
+{
+    if (discovering_)
+    {
+        return {false, "PLC 自动搜索正在进行"};
+    }
+    PlcSerialConfiguration validation_configuration = preferred;
+    validation_configuration.portName = "DISCOVERY";
+    const PlcCommunicationResult validation =
+        validatePlcSerialConfiguration(validation_configuration);
+    if (!validation.succeeded)
+    {
+        return validation;
+    }
+
+    std::vector<std::string> available_ports;
+    for (const QSerialPortInfo &port : QSerialPortInfo::availablePorts())
+    {
+        available_ports.push_back(toUtf8(port.portName()));
+    }
+    candidates_ = buildPlcDiscoveryCandidates(preferred, available_ports);
+    if (candidates_.empty())
+    {
+        return {false, "没有检测到可用串口"};
+    }
+    if (master_->state() != QModbusDevice::UnconnectedState)
+    {
+        return {false, "自动搜索串口尚未释放，请稍后重试"};
+    }
+
+    current_candidate_ = 0;
+    pending_reply_.clear();
+    phase_ = Phase::Idle;
+    discovering_ = true;
+    cancel_requested_ = false;
+    found_pending_ = false;
+    ++attempt_generation_;
+    QTimer::singleShot(
+        kDiscoveryStartDelayMs,
+        this,
+        &PlcDiscoveryService::tryCurrentCandidate);
+    return {true, {}};
+}
+
+void PlcDiscoveryService::cancelDiscovery()
+{
+    if (!discovering_ || cancel_requested_)
+    {
+        return;
+    }
+    cancel_requested_ = true;
+    found_pending_ = false;
+    ++attempt_generation_;
+    disconnectCurrent(false);
+}
+
+bool PlcDiscoveryService::isDiscovering() const
+{
+    return discovering_;
+}
+
+void PlcDiscoveryService::setCallbacks(
+    std::function<void(const PlcDiscoveryProgress &)> progress_changed,
+    std::function<void(const PlcDiscoveryOutcome &)> discovery_finished)
+{
+    progress_changed_callback_ = std::move(progress_changed);
+    discovery_finished_callback_ = std::move(discovery_finished);
+}
+
+void PlcDiscoveryService::tryCurrentCandidate()
+{
+    if (!discovering_)
+    {
+        return;
+    }
+    if (cancel_requested_)
+    {
+        disconnectCurrent(false);
+        return;
+    }
+    if (current_candidate_ >= candidates_.size())
+    {
+        finishDiscovery({
+            false, false, {},
+            "未找到可响应的 PLC，请检查站号、接线和 PLC RTU 设置"});
+        return;
+    }
+
+    const PlcSerialConfiguration &candidate = candidates_.at(current_candidate_);
+    if (progress_changed_callback_)
+    {
+        progress_changed_callback_({
+            candidate, current_candidate_ + 1U, candidates_.size()});
+    }
+    ++attempt_generation_;
+    phase_ = Phase::Connecting;
+    master_->setConnectionParameter(
+        QModbusDevice::SerialPortNameParameter,
+        QString::fromUtf8(candidate.portName.c_str()));
+    master_->setConnectionParameter(
+        QModbusDevice::SerialBaudRateParameter, candidate.baudRate);
+    master_->setConnectionParameter(
+        QModbusDevice::SerialDataBitsParameter,
+        static_cast<QSerialPort::DataBits>(candidate.dataBits));
+    master_->setConnectionParameter(
+        QModbusDevice::SerialParityParameter,
+        static_cast<QSerialPort::Parity>(candidate.parity));
+    master_->setConnectionParameter(
+        QModbusDevice::SerialStopBitsParameter,
+        static_cast<QSerialPort::StopBits>(candidate.stopBits));
+    master_->setTimeout(kDiscoveryResponseTimeoutMs);
+    master_->setNumberOfRetries(0);
+    if (!master_->connectDevice())
+    {
+        QTimer::singleShot(
+            0, this,
+            [this]
+            {
+                if (discovering_ && phase_ == Phase::Connecting)
+                {
+                    disconnectCurrent(false);
+                }
+            });
+    }
+}
+
+void PlcDiscoveryService::sendProbe()
+{
+    if (!discovering_ || cancel_requested_
+        || current_candidate_ >= candidates_.size())
+    {
+        disconnectCurrent(false);
+        return;
+    }
+    phase_ = Phase::Probing;
+    const PlcSerialConfiguration &candidate = candidates_.at(current_candidate_);
+    const QModbusDataUnit request(
+        QModbusDataUnit::HoldingRegisters, 0, 1);
+    QModbusReply *reply = master_->sendReadRequest(
+        request, candidate.serverAddress);
+    if (reply == nullptr)
+    {
+        disconnectCurrent(false);
+        return;
+    }
+    pending_reply_ = reply;
+    const std::uint64_t generation = attempt_generation_;
+    connect(
+        reply, &QModbusReply::finished,
+        this,
+        [this, reply, generation]
+        {
+            handleProbeFinished(reply, generation);
+        });
+}
+
+void PlcDiscoveryService::handleProbeFinished(
+    QModbusReply *reply,
+    std::uint64_t attempt_generation)
+{
+    const bool is_current_attempt = discovering_
+        && !cancel_requested_
+        && phase_ == Phase::Probing
+        && attempt_generation == attempt_generation_;
+    if (pending_reply_ == reply)
+    {
+        pending_reply_.clear();
+    }
+    const bool valid_response = reply->error() == QModbusDevice::NoError
+        || reply->rawResult().isException();
+    reply->deleteLater();
+    if (is_current_attempt)
+    {
+        disconnectCurrent(valid_response);
+    }
+}
+
+void PlcDiscoveryService::disconnectCurrent(bool found)
+{
+    if (!discovering_)
+    {
+        return;
+    }
+    found_pending_ = found && !cancel_requested_;
+    phase_ = Phase::Disconnecting;
+    if (master_->state() == QModbusDevice::UnconnectedState)
+    {
+        QTimer::singleShot(0, this, &PlcDiscoveryService::continueAfterDisconnect);
+        return;
+    }
+    master_->disconnectDevice();
+}
+
+void PlcDiscoveryService::continueAfterDisconnect()
+{
+    if (!discovering_ || phase_ != Phase::Disconnecting)
+    {
+        return;
+    }
+    if (cancel_requested_)
+    {
+        finishDiscovery({false, true, {}, {}});
+        return;
+    }
+    if (found_pending_)
+    {
+        finishDiscovery({
+            true, false, candidates_.at(current_candidate_),
+            "已找到 PLC，正在连接"});
+        return;
+    }
+    ++current_candidate_;
+    phase_ = Phase::Idle;
+    QTimer::singleShot(0, this, &PlcDiscoveryService::tryCurrentCandidate);
+}
+
+void PlcDiscoveryService::finishDiscovery(const PlcDiscoveryOutcome &outcome)
+{
+    discovering_ = false;
+    cancel_requested_ = false;
+    found_pending_ = false;
+    pending_reply_.clear();
+    phase_ = Phase::Idle;
+    ++attempt_generation_;
+    if (discovery_finished_callback_)
+    {
+        discovery_finished_callback_(outcome);
+    }
+    candidates_.clear();
+    current_candidate_ = 0;
+}
+
+void PlcDiscoveryService::handleDeviceStateChanged(QModbusDevice::State state)
+{
+    if (!discovering_)
+    {
+        return;
+    }
+    if (state == QModbusDevice::ConnectedState && phase_ == Phase::Connecting)
+    {
+        sendProbe();
+        return;
+    }
+    if (state == QModbusDevice::UnconnectedState)
+    {
+        if (phase_ == Phase::Disconnecting)
+        {
+            QTimer::singleShot(0, this, &PlcDiscoveryService::continueAfterDisconnect);
+        }
+        else if (phase_ == Phase::Connecting || phase_ == Phase::Probing)
+        {
+            disconnectCurrent(false);
+        }
+    }
+}

app/src/infrastructure/plc_discovery_service.h

@@ -0,0 +1,68 @@
+#pragma once
+
+#include "services/plc_discovery_gateway.h"
+
+#include <QModbusDevice>
+#include <QObject>
+#include <QPointer>
+
+#include <cstddef>
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <vector>
+
+class QModbusReply;
+class QModbusRtuSerialMaster;
+
+// 使用独立 Qt Modbus RTU 主站逐项探测串口参数，不污染正式 PLC 连接状态
+class PlcDiscoveryService final : public QObject, public PlcDiscoveryGateway
+{
+public:
+    explicit PlcDiscoveryService(QObject *parent = nullptr);
+    ~PlcDiscoveryService() override;
+
+    PlcCommunicationResult startDiscovery(
+        const PlcSerialConfiguration &preferred) override;
+    void cancelDiscovery() override;
+    bool isDiscovering() const override;
+    void setCallbacks(
+        std::function<void(const PlcDiscoveryProgress &)> progress_changed,
+        std::function<void(const PlcDiscoveryOutcome &)> discovery_finished) override;
+
+private:
+    enum class Phase
+    {
+        Idle,
+        Connecting,
+        Probing,
+        Disconnecting
+    };
+
+    // 尝试当前候选参数并等待串口异步打开
+    void tryCurrentCandidate();
+    // 串口打开后发送只读 D0 探测请求
+    void sendProbe();
+    // 处理当前 D0 探测结果
+    void handleProbeFinished(QModbusReply *reply, std::uint64_t attempt_generation);
+    // 释放当前串口，释放完成后进入下一个候选或报告结果
+    void disconnectCurrent(bool found);
+    // 当前串口完全释放后完成状态迁移
+    void continueAfterDisconnect();
+    // 报告最终结果并清理搜索状态
+    void finishDiscovery(const PlcDiscoveryOutcome &outcome);
+    // 处理 Qt Modbus 主站连接状态变化
+    void handleDeviceStateChanged(QModbusDevice::State state);
+
+    std::unique_ptr<QModbusRtuSerialMaster> master_;
+    std::vector<PlcSerialConfiguration> candidates_;
+    std::size_t current_candidate_ = 0;
+    QPointer<QModbusReply> pending_reply_;
+    Phase phase_ = Phase::Idle;
+    bool discovering_ = false;
+    bool cancel_requested_ = false;
+    bool found_pending_ = false;
+    std::uint64_t attempt_generation_ = 0;
+    std::function<void(const PlcDiscoveryProgress &)> progress_changed_callback_;
+    std::function<void(const PlcDiscoveryOutcome &)> discovery_finished_callback_;
+};

app/src/main.cpp

@@ -10,6 +10,7 @@
 
 #include "infrastructure/json_project_storage.h"
 #include "infrastructure/plc_communication_service.h"
+#include "infrastructure/plc_discovery_service.h"
 #include "infrastructure/plc_register_repository.h"
 #include "domain/active_register_repository.h"
 #include "domain/virtual_register_repository.h"
@@ -57,6 +58,8 @@ int main(int argc, char *argv[])
     ActiveRegisterRepository active_register_repository(virtual_register_repository);
     // 负责通过串口异步连接、读取和写入真实 PLC
     PlcCommunicationService plc_communication_service(plc_register_repository);
+    // 使用独立串口会话自动搜索 PLC，不影响正式通信状态机
+    PlcDiscoveryService plc_discovery_service;
     // 处理运行画面读取和写入寄存器，数据来自当前选中的寄存器入口
     HmiRuntimeService hmi_runtime_service(active_register_repository);
 
@@ -91,7 +94,8 @@ int main(int argc, char *argv[])
         alarm_service,
         hmi_navigation_service,
         register_comment_service,
-        register_monitor_service);
+        register_monitor_service,
+        plc_discovery_service);
     // 把主窗口显示到屏幕上
     main_window.show();
 

app/src/services/plc_discovery_gateway.cpp

@@ -0,0 +1,126 @@
+#include "plc_discovery_gateway.h"
+
+#include <algorithm>
+#include <array>
+#include <tuple>
+#include <utility>
+
+namespace {
+
+struct SerialFrame
+{
+    int dataBits = 8;
+    int parity = 2;
+    int stopBits = 1;
+};
+
+bool isSupportedBaudRate(int baud_rate)
+{
+    return baud_rate == 9600
+        || baud_rate == 19200
+        || baud_rate == 38400
+        || baud_rate == 57600
+        || baud_rate == 115200;
+}
+
+bool isSupportedFrame(const SerialFrame &frame)
+{
+    return (frame.dataBits == 7 || frame.dataBits == 8)
+        && (frame.parity == 0 || frame.parity == 2 || frame.parity == 3)
+        && (frame.stopBits == 1 || frame.stopBits == 2);
+}
+
+bool sameFrame(const SerialFrame &left, const SerialFrame &right)
+{
+    return std::tie(left.dataBits, left.parity, left.stopBits)
+        == std::tie(right.dataBits, right.parity, right.stopBits);
+}
+
+template<typename Value, typename Equals>
+void appendUnique(std::vector<Value> *values, Value value, Equals equals)
+{
+    if (std::none_of(
+            values->cbegin(), values->cend(),
+            [&value, &equals](const Value &existing) { return equals(existing, value); }))
+    {
+        values->push_back(std::move(value));
+    }
+}
+
+} // namespace
+
+std::vector<PlcSerialConfiguration> buildPlcDiscoveryCandidates(
+    const PlcSerialConfiguration &preferred,
+    const std::vector<std::string> &available_ports)
+{
+    std::vector<std::string> ports;
+    ports.reserve(available_ports.size());
+    for (const std::string &port : available_ports)
+    {
+        if (!port.empty())
+        {
+            appendUnique(
+                &ports, port,
+                [](const std::string &left, const std::string &right) {
+                    return left == right;
+                });
+        }
+    }
+    const auto preferred_port = std::find(
+        ports.begin(), ports.end(), preferred.portName);
+    if (preferred_port != ports.end())
+    {
+        std::rotate(ports.begin(), preferred_port, preferred_port + 1);
+    }
+
+    std::vector<int> baud_rates;
+    if (isSupportedBaudRate(preferred.baudRate))
+    {
+        baud_rates.push_back(preferred.baudRate);
+    }
+    constexpr std::array<int, 5> kSupportedBaudRates{
+        9600, 19200, 38400, 57600, 115200};
+    for (int baud_rate : kSupportedBaudRates)
+    {
+        appendUnique(
+            &baud_rates, baud_rate,
+            [](int left, int right) { return left == right; });
+    }
+
+    std::vector<SerialFrame> frames;
+    const SerialFrame preferred_frame{
+        preferred.dataBits, preferred.parity, preferred.stopBits};
+    if (isSupportedFrame(preferred_frame))
+    {
+        frames.push_back(preferred_frame);
+    }
+    constexpr std::array<SerialFrame, 12> kSupportedFrames{{
+        {8, 2, 1}, {8, 0, 1}, {8, 3, 1},
+        {8, 0, 2}, {8, 2, 2}, {8, 3, 2},
+        {7, 2, 1}, {7, 3, 1}, {7, 0, 1},
+        {7, 0, 2}, {7, 2, 2}, {7, 3, 2}}};
+    for (const SerialFrame &frame : kSupportedFrames)
+    {
+        appendUnique(&frames, frame, sameFrame);
+    }
+
+    std::vector<PlcSerialConfiguration> candidates;
+    candidates.reserve(ports.size() * baud_rates.size() * frames.size());
+    for (const SerialFrame &frame : frames)
+    {
+        for (int baud_rate : baud_rates)
+        {
+            for (const std::string &port : ports)
+            {
+                PlcSerialConfiguration candidate = preferred;
+                candidate.portName = port;
+                candidate.baudRate = baud_rate;
+                candidate.dataBits = frame.dataBits;
+                candidate.parity = frame.parity;
+                candidate.stopBits = frame.stopBits;
+                candidates.push_back(std::move(candidate));
+            }
+        }
+    }
+    return candidates;
+}

app/src/services/plc_discovery_gateway.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include "plc_communication_gateway.h"
+
+#include <cstddef>
+#include <functional>
+#include <string>
+#include <vector>
+
+// 自动搜索正在尝试的串口参数和总体进度
+struct PlcDiscoveryProgress
+{
+    PlcSerialConfiguration configuration;
+    std::size_t currentAttempt = 0;
+    std::size_t totalAttempts = 0;
+};
+
+// 自动搜索结束结果；found 和 cancelled 不会同时为 true
+struct PlcDiscoveryOutcome
+{
+    bool found = false;
+    bool cancelled = false;
+    PlcSerialConfiguration configuration;
+    std::string message;
+};
+
+/**
+ * 按优先级生成搜索组合
+ *
+ * 站号和通信时序沿用界面当前值，只遍历可用端口及项目支持的串口参数
+ */
+std::vector<PlcSerialConfiguration> buildPlcDiscoveryCandidates(
+    const PlcSerialConfiguration &preferred,
+    const std::vector<std::string> &available_ports);
+
+// UI 使用的异步 PLC 自动搜索契约，具体串口实现位于 infrastructure
+class PlcDiscoveryGateway
+{
+public:
+    virtual ~PlcDiscoveryGateway() = default;
+
+    // 开始搜索，实际进度和结果通过回调通知
+    virtual PlcCommunicationResult startDiscovery(
+        const PlcSerialConfiguration &preferred) = 0;
+    // 取消当前搜索；串口释放后通过结束回调通知
+    virtual void cancelDiscovery() = 0;
+    // 返回当前是否正在搜索或等待释放搜索串口
+    virtual bool isDiscovering() const = 0;
+    // 替换进度和结束回调，传入空函数可取消通知
+    virtual void setCallbacks(
+        std::function<void(const PlcDiscoveryProgress &)> progress_changed,
+        std::function<void(const PlcDiscoveryOutcome &)> discovery_finished) = 0;
+};

app/src/ui/main_window.cpp

@@ -29,6 +29,7 @@
 #include <QAbstractSpinBox>
 #include <QApplication>
 #include <QCloseEvent>
+#include <QDialogButtonBox>
 #include <QEvent>
 #include <QFileDialog>
 #include <QGraphicsScene>
@@ -41,6 +42,7 @@
 #include <QMessageBox>
 #include <QMenu>
 #include <QPlainTextEdit>
+#include <QPushButton>
 #include <QStatusBar>
 #include <QTabWidget>
 #include <QToolBar>
@@ -68,6 +70,55 @@ bool isTextEditingObject(QObject *object)
     return false;
 }
 
+QString suggestedProjectFileName(QString project_name)
+{
+    project_name = project_name.trimmed();
+    const QString invalid_characters = QStringLiteral("<>:\"/\\|?*");
+    for (QChar &character : project_name)
+    {
+        if (character.unicode() < 0x20U || invalid_characters.contains(character))
+        {
+            character = QLatin1Char('_');
+        }
+    }
+
+    constexpr int kMaximumSuggestedBaseNameLength = 240;
+    if (project_name.size() > kMaximumSuggestedBaseNameLength)
+    {
+        project_name.truncate(kMaximumSuggestedBaseNameLength);
+        if (!project_name.isEmpty()
+            && project_name.at(project_name.size() - 1).isHighSurrogate())
+        {
+            project_name.chop(1);
+        }
+    }
+    while (project_name.endsWith(QLatin1Char(' '))
+           || project_name.endsWith(QLatin1Char('.')))
+    {
+        project_name.chop(1);
+    }
+    if (project_name.isEmpty())
+    {
+        project_name = QStringLiteral("未命名工程");
+    }
+
+    const QString device_name = project_name.section(QLatin1Char('.'), 0, 0).toUpper();
+    const bool is_reserved_device_name = device_name == QStringLiteral("CON")
+        || device_name == QStringLiteral("PRN")
+        || device_name == QStringLiteral("AUX")
+        || device_name == QStringLiteral("NUL")
+        || (device_name.size() == 4
+            && (device_name.startsWith(QStringLiteral("COM"))
+                || device_name.startsWith(QStringLiteral("LPT")))
+            && device_name.back() >= QLatin1Char('1')
+            && device_name.back() <= QLatin1Char('9'));
+    if (is_reserved_device_name)
+    {
+        project_name.prepend(QLatin1Char('_'));
+    }
+    return project_name + QStringLiteral(".json");
+}
+
 bool isEditorShortcut(const QKeyEvent &event)
 {
     return event.matches(QKeySequence::Undo)
@@ -210,6 +261,7 @@ MainWindow::MainWindow(
     AlarmService &alarm_service,
     RegisterCommentService &register_comment_service,
     RegisterMonitorService &register_monitor_service,
+    PlcDiscoveryGateway &plc_discovery_gateway,
     QWidget *parent)
     : QMainWindow(parent),
       ui_(std::make_unique<Ui::MainWindow>()),
@@ -222,6 +274,7 @@ MainWindow::MainWindow(
       alarm_service_(alarm_service),
       register_comment_service_(register_comment_service),
       register_monitor_service_(register_monitor_service),
+      plc_discovery_gateway_(plc_discovery_gateway),
       owned_hmi_navigation_service_(
           std::make_unique<HmiNavigationService>(project_service)),
       hmi_navigation_service_(owned_hmi_navigation_service_.get())
@@ -240,6 +293,7 @@ MainWindow::MainWindow(
     HmiNavigationService &hmi_navigation_service,
     RegisterCommentService &register_comment_service,
     RegisterMonitorService &register_monitor_service,
+    PlcDiscoveryGateway &plc_discovery_gateway,
     QWidget *parent)
     : QMainWindow(parent),
       ui_(std::make_unique<Ui::MainWindow>()),
@@ -252,6 +306,7 @@ MainWindow::MainWindow(
       alarm_service_(alarm_service),
       register_comment_service_(register_comment_service),
       register_monitor_service_(register_monitor_service),
+      plc_discovery_gateway_(plc_discovery_gateway),
       hmi_navigation_service_(&hmi_navigation_service)
 {
     initializeUi();
@@ -1204,7 +1259,11 @@ void MainWindow::updateProjectTreeActions()
 
 void MainWindow::connectPlc()
 {
-    PlcConnectionDialog dialog(plc_configuration_, this);
+    PlcConnectionDialog dialog(
+        plc_configuration_,
+        plc_discovery_gateway_,
+        [this] { runtime_mode_service_.disconnectPlc(); },
+        this);
     if (dialog.exec() != QDialog::Accepted)
     {
         return;
@@ -1466,12 +1525,32 @@ void MainWindow::createNewProject()
     {
         return;
     }
-    const QString name = QInputDialog::getText(
-        this, tr("新建工程"), tr("工程名称"));
-    if (name.isEmpty())
+
+    QInputDialog name_dialog(this);
+    name_dialog.setWindowTitle(tr("新建工程"));
+    name_dialog.setLabelText(tr("工程名称"));
+    name_dialog.setInputMode(QInputDialog::TextInput);
+
+    QDialogButtonBox *button_box = name_dialog.findChild<QDialogButtonBox *>();
+    QPushButton *ok_button = button_box != nullptr
+        ? button_box->button(QDialogButtonBox::Ok)
+        : nullptr;
+    if (ok_button != nullptr)
+    {
+        ok_button->setEnabled(false);
+        connect(&name_dialog,
+                &QInputDialog::textValueChanged,
+                &name_dialog,
+                [ok_button](const QString &text) {
+                    ok_button->setEnabled(!text.trimmed().isEmpty());
+                });
+    }
+
+    if (name_dialog.exec() != QDialog::Accepted)
     {
         return;
     }
+    const QString name = name_dialog.textValue().trimmed();
     const ProjectOperationResult result = project_service_.createNewProject(toUtf8(name));
     if (!result.succeeded)
     {
@@ -1512,8 +1591,13 @@ void MainWindow::saveProject()
 
 void MainWindow::saveProjectAs()
 {
+    const QString suggested_file_name = suggestedProjectFileName(
+        fromUtf8(project_service_.project().metadata.name));
     const QString path = QFileDialog::getSaveFileName(
-        this, tr("工程另存为"), {}, tr("工程文件 (*.json)"));
+        this,
+        tr("工程另存为"),
+        suggested_file_name,
+        tr("工程文件 (*.json)"));
     if (path.isEmpty())
     {
         return;

app/src/ui/main_window.h

@@ -43,6 +43,7 @@ class HmiEditorWidget;
 class LogicEditorService;
 class LogicEditorWidget;
 class RegisterMonitorService;
+class PlcDiscoveryGateway;
 class RuntimeMonitorWidget;
 class ProjectWorkspaceController;
 class PropertyPanelController;
@@ -77,6 +78,7 @@ public:
         AlarmService &alarm_service,
         RegisterCommentService &register_comment_service,
         RegisterMonitorService &register_monitor_service,
+        PlcDiscoveryGateway &plc_discovery_gateway,
         QWidget *parent = nullptr);
     /**
      * @brief 创建主窗口，并使用调用方提供的 HMI 页面导航服务
@@ -94,6 +96,7 @@ public:
         HmiNavigationService &hmi_navigation_service,
         RegisterCommentService &register_comment_service,
         RegisterMonitorService &register_monitor_service,
+        PlcDiscoveryGateway &plc_discovery_gateway,
         QWidget *parent = nullptr);
 
     /** 释放窗口拥有的控制器和可选导航服务 */
@@ -251,6 +254,8 @@ private:
     RegisterCommentService &register_comment_service_;
     /** 非拥有的寄存器监控服务依赖 */
     RegisterMonitorService &register_monitor_service_;
+    /** 非拥有的 PLC 自动搜索服务依赖 */
+    PlcDiscoveryGateway &plc_discovery_gateway_;
     /** 当调用方未提供导航服务时由主窗口负责拥有的实例 */
     std::unique_ptr<HmiNavigationService> owned_hmi_navigation_service_;
     /** 当前使用的 HMI 页面导航服务 */

app/src/ui/plc_connection_dialog.cpp

@@ -3,9 +3,17 @@
 #include "ui_plc_connection_dialog.h"
 
 #include <QComboBox>
+#include <QDialogButtonBox>
+#include <QMessageBox>
+#include <QProgressBar>
+#include <QPushButton>
 #include <QSerialPortInfo>
+#include <QStyle>
+#include <QTimer>
+#include <QToolButton>
 
 #include <initializer_list>
+#include <utility>
 
 namespace {
 
@@ -32,9 +40,13 @@ void selectData(QComboBox *combo_box, int value)
 
 PlcConnectionDialog::PlcConnectionDialog(
     const PlcSerialConfiguration &configuration,
+    PlcDiscoveryGateway &discovery_gateway,
+    std::function<void()> prepare_discovery,
     QWidget *parent)
     : QDialog(parent),
-      ui_(std::make_unique<Ui::PlcConnectionDialog>())
+      ui_(std::make_unique<Ui::PlcConnectionDialog>()),
+      discovery_gateway_(discovery_gateway),
+      prepare_discovery_(std::move(prepare_discovery))
 {
     ui_->setupUi(this);
     setItemData(ui_->baudRateComboBox, {9600, 19200, 38400, 57600, 115200});
@@ -42,22 +54,8 @@ PlcConnectionDialog::PlcConnectionDialog(
     setItemData(ui_->parityComboBox, {0, 3, 2});
     setItemData(ui_->stopBitsComboBox, {1, 2});
 
-    for (const QSerialPortInfo &port : QSerialPortInfo::availablePorts())
-    {
-        ui_->serialPortComboBox->addItem(
-            port.portName(),
-            port.description().isEmpty() ? port.portName() : port.description());
-    }
     const QString port_name = QString::fromUtf8(configuration.portName.c_str());
-    if (!port_name.isEmpty())
-    {
-        const int port_index = ui_->serialPortComboBox->findText(port_name);
-        if (port_index < 0)
-        {
-            ui_->serialPortComboBox->addItem(port_name);
-        }
-        ui_->serialPortComboBox->setCurrentText(port_name);
-    }
+    refreshSerialPorts(port_name);
 
     ui_->serverAddressSpinBox->setValue(configuration.serverAddress);
     selectData(ui_->baudRateComboBox, configuration.baudRate);
@@ -67,9 +65,36 @@ PlcConnectionDialog::PlcConnectionDialog(
     ui_->responseTimeoutSpinBox->setValue(configuration.responseTimeoutMs);
     ui_->retriesSpinBox->setValue(configuration.retries);
     ui_->pollIntervalSpinBox->setValue(configuration.pollIntervalMs);
+
+    ui_->autoSearchButton->setIcon(style()->standardIcon(QStyle::SP_BrowserReload));
+    ui_->refreshPortsButton->setIcon(style()->standardIcon(QStyle::SP_BrowserReload));
+    ui_->discoveryProgressBar->setVisible(false);
+    connect(
+        ui_->refreshPortsButton, &QToolButton::clicked,
+        this,
+        [this]
+        {
+            refreshSerialPorts(ui_->serialPortComboBox->currentText().trimmed());
+        });
+    connect(
+        ui_->autoSearchButton, &QPushButton::clicked,
+        this, &PlcConnectionDialog::toggleAutomaticDiscovery);
+    discovery_gateway_.setCallbacks(
+        [this](const PlcDiscoveryProgress &progress)
+        {
+            showDiscoveryProgress(progress);
+        },
+        [this](const PlcDiscoveryOutcome &outcome)
+        {
+            handleDiscoveryFinished(outcome);
+        });
 }
 
-PlcConnectionDialog::~PlcConnectionDialog() = default;
+PlcConnectionDialog::~PlcConnectionDialog()
+{
+    discovery_gateway_.setCallbacks({}, {});
+    discovery_gateway_.cancelDiscovery();
+}
 
 PlcSerialConfiguration PlcConnectionDialog::configuration() const
 {
@@ -86,3 +111,139 @@ PlcSerialConfiguration PlcConnectionDialog::configuration() const
     result.pollIntervalMs = ui_->pollIntervalSpinBox->value();
     return result;
 }
+
+void PlcConnectionDialog::refreshSerialPorts(const QString &preferred_port)
+{
+    ui_->serialPortComboBox->clear();
+    for (const QSerialPortInfo &port : QSerialPortInfo::availablePorts())
+    {
+        ui_->serialPortComboBox->addItem(
+            port.portName(),
+            port.description().isEmpty() ? port.portName() : port.description());
+    }
+    const int preferred_index = ui_->serialPortComboBox->findText(preferred_port);
+    if (preferred_index >= 0)
+    {
+        ui_->serialPortComboBox->setCurrentIndex(preferred_index);
+    }
+    else if (ui_->serialPortComboBox->count() > 0)
+    {
+        ui_->serialPortComboBox->setCurrentIndex(0);
+    }
+    else
+    {
+        ui_->serialPortComboBox->clearEditText();
+    }
+}
+
+void PlcConnectionDialog::toggleAutomaticDiscovery()
+{
+    if (discovery_gateway_.isDiscovering())
+    {
+        ui_->autoSearchButton->setEnabled(false);
+        ui_->autoSearchButton->setText(tr("正在停止"));
+        discovery_gateway_.cancelDiscovery();
+        return;
+    }
+    const PlcCommunicationResult result = discovery_gateway_.startDiscovery(
+        configuration());
+    if (!result.succeeded)
+    {
+        const QString message = QString::fromUtf8(result.message.c_str());
+        ui_->discoveryStatusLabel->setText(message);
+        QMessageBox::information(this, tr("自动搜索 PLC"), message);
+        return;
+    }
+    if (prepare_discovery_)
+    {
+        prepare_discovery_();
+    }
+    setDiscoveryUiActive(true);
+}
+
+void PlcConnectionDialog::showDiscoveryProgress(
+    const PlcDiscoveryProgress &progress)
+{
+    const PlcSerialConfiguration &candidate = progress.configuration;
+    const QChar parity = candidate.parity == 2
+        ? QLatin1Char('E')
+        : candidate.parity == 3 ? QLatin1Char('O') : QLatin1Char('N');
+    ui_->discoveryProgressBar->setMaximum(
+        static_cast<int>(progress.totalAttempts));
+    ui_->discoveryProgressBar->setValue(
+        static_cast<int>(progress.currentAttempt));
+    ui_->discoveryStatusLabel->setText(
+        tr("正在搜索 %1：站号 %2，%3，%4%5%6（%7/%8）")
+            .arg(QString::fromUtf8(candidate.portName.c_str()))
+            .arg(candidate.serverAddress)
+            .arg(candidate.baudRate)
+            .arg(candidate.dataBits)
+            .arg(parity)
+            .arg(candidate.stopBits)
+            .arg(progress.currentAttempt)
+            .arg(progress.totalAttempts));
+}
+
+void PlcConnectionDialog::handleDiscoveryFinished(
+    const PlcDiscoveryOutcome &outcome)
+{
+    setDiscoveryUiActive(false);
+    if (outcome.cancelled)
+    {
+        ui_->discoveryStatusLabel->setText(tr("已停止自动搜索"));
+        return;
+    }
+    if (!outcome.found)
+    {
+        const QString message = outcome.message.empty()
+            ? tr("未找到可响应的 PLC")
+            : QString::fromUtf8(outcome.message.c_str());
+        ui_->discoveryStatusLabel->setText(message);
+        QMessageBox::information(this, tr("自动搜索 PLC"), message);
+        return;
+    }
+    applyConfiguration(outcome.configuration);
+    ui_->discoveryStatusLabel->setText(tr("已找到 PLC，正在连接"));
+    QTimer::singleShot(0, this, &QDialog::accept);
+}
+
+void PlcConnectionDialog::setDiscoveryUiActive(bool active)
+{
+    ui_->discoveryProgressBar->setVisible(active);
+    ui_->serialPortComboBox->setEnabled(!active);
+    ui_->refreshPortsButton->setEnabled(!active);
+    ui_->serverAddressSpinBox->setEnabled(!active);
+    ui_->baudRateComboBox->setEnabled(!active);
+    ui_->dataBitsComboBox->setEnabled(!active);
+    ui_->parityComboBox->setEnabled(!active);
+    ui_->stopBitsComboBox->setEnabled(!active);
+    ui_->timingGroupBox->setEnabled(!active);
+    QPushButton *ok_button = ui_->buttonBox->button(QDialogButtonBox::Ok);
+    if (ok_button != nullptr)
+    {
+        ok_button->setEnabled(!active);
+    }
+    ui_->autoSearchButton->setEnabled(true);
+    ui_->autoSearchButton->setText(active ? tr("停止搜索") : tr("自动搜索"));
+    ui_->autoSearchButton->setIcon(style()->standardIcon(
+        active ? QStyle::SP_BrowserStop : QStyle::SP_BrowserReload));
+}
+
+void PlcConnectionDialog::applyConfiguration(
+    const PlcSerialConfiguration &configuration)
+{
+    const QString port_name = QString::fromUtf8(configuration.portName.c_str());
+    if (ui_->serialPortComboBox->findText(port_name) < 0)
+    {
+        ui_->serialPortComboBox->addItem(port_name);
+    }
+    ui_->serialPortComboBox->setCurrentText(port_name);
+    ui_->serverAddressSpinBox->setValue(configuration.serverAddress);
+    selectData(ui_->baudRateComboBox, configuration.baudRate);
+    selectData(ui_->dataBitsComboBox, configuration.dataBits);
+    selectData(ui_->parityComboBox, configuration.parity);
+    selectData(ui_->stopBitsComboBox, configuration.stopBits);
+    ui_->responseTimeoutSpinBox->setValue(configuration.responseTimeoutMs);
+    ui_->retriesSpinBox->setValue(configuration.retries);
+    ui_->pollIntervalSpinBox->setValue(configuration.pollIntervalMs);
+}

app/src/ui/plc_connection_dialog.h

@@ -9,9 +9,12 @@
 #pragma once
 
 #include "services/plc_communication_gateway.h"
+#include "services/plc_discovery_gateway.h"
 
 #include <QDialog>
+#include <QString>
 
+#include <functional>
 #include <memory>
 
 namespace Ui {
@@ -27,6 +30,8 @@ public:
     /** 使用现有配置初始化 PLC 参数表单 */
     explicit PlcConnectionDialog(
         const PlcSerialConfiguration &configuration,
+        PlcDiscoveryGateway &discovery_gateway,
+        std::function<void()> prepare_discovery,
         QWidget *parent = nullptr);
     /** 释放 Designer 界面对象 */
     ~PlcConnectionDialog() override;
@@ -35,6 +40,23 @@ public:
     PlcSerialConfiguration configuration() const;
 
 private:
+    /** 重新枚举当前实际存在的串口，并尽量保留仍然可用的选择 */
+    void refreshSerialPorts(const QString &preferred_port);
+    /** 开始自动搜索或请求停止当前搜索 */
+    void toggleAutomaticDiscovery();
+    /** 根据异步探测进度刷新界面 */
+    void showDiscoveryProgress(const PlcDiscoveryProgress &progress);
+    /** 处理找到、未找到和用户取消三种结束结果 */
+    void handleDiscoveryFinished(const PlcDiscoveryOutcome &outcome);
+    /** 切换搜索期间的表单编辑权限和按钮状态 */
+    void setDiscoveryUiActive(bool active);
+    /** 把一组串口配置回填到界面 */
+    void applyConfiguration(const PlcSerialConfiguration &configuration);
+
     /** Qt Designer 生成的界面对象 */
     std::unique_ptr<Ui::PlcConnectionDialog> ui_;
+    /** 异步 PLC 自动搜索服务 */
+    PlcDiscoveryGateway &discovery_gateway_;
+    /** 搜索前释放正式 PLC 连接占用的串口 */
+    std::function<void()> prepare_discovery_;
 };

app/src/ui/plc_connection_dialog.ui

@@ -6,54 +6,94 @@
    <string>PLC 通信配置</string>
   </property>
   <property name="minimumSize">
-   <size><width>420</width><height>0</height></size>
+   <size><width>440</width><height>0</height></size>
   </property>
   <layout class="QVBoxLayout" name="dialogLayout">
    <item>
     <widget class="QGroupBox" name="serialGroupBox">
      <property name="title"><string>Modbus RTU 串口</string></property>
-     <layout class="QFormLayout" name="serialFormLayout">
-      <property name="fieldGrowthPolicy"><enum>QFormLayout::AllNonFixedFieldsGrow</enum></property>
-      <item row="0" column="0"><widget class="QLabel" name="serialPortLabel"><property name="text"><string>端口</string></property></widget></item>
-      <item row="0" column="1">
-       <widget class="QComboBox" name="serialPortComboBox">
-        <property name="editable"><bool>true</bool></property>
-        <property name="placeholderText"><string>选择或输入 COM 端口</string></property>
-       </widget>
-      </item>
-      <item row="1" column="0"><widget class="QLabel" name="serverAddressLabel"><property name="text"><string>PLC 站号</string></property></widget></item>
-      <item row="1" column="1"><widget class="QSpinBox" name="serverAddressSpinBox"><property name="minimum"><number>1</number></property><property name="maximum"><number>247</number></property></widget></item>
-      <item row="2" column="0"><widget class="QLabel" name="baudRateLabel"><property name="text"><string>波特率</string></property></widget></item>
-      <item row="2" column="1">
-       <widget class="QComboBox" name="baudRateComboBox">
-        <item><property name="text"><string>9600</string></property><property name="userData"><string notr="true">9600</string></property></item>
-        <item><property name="text"><string>19200</string></property><property name="userData"><string notr="true">19200</string></property></item>
-        <item><property name="text"><string>38400</string></property><property name="userData"><string notr="true">38400</string></property></item>
-        <item><property name="text"><string>57600</string></property><property name="userData"><string notr="true">57600</string></property></item>
-        <item><property name="text"><string>115200</string></property><property name="userData"><string notr="true">115200</string></property></item>
-       </widget>
+     <layout class="QVBoxLayout" name="serialGroupLayout">
+      <item>
+       <layout class="QHBoxLayout" name="discoveryControlLayout">
+        <item>
+         <widget class="QPushButton" name="autoSearchButton">
+          <property name="text"><string>自动搜索</string></property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QProgressBar" name="discoveryProgressBar">
+          <property name="minimum"><number>0</number></property>
+          <property name="maximum"><number>100</number></property>
+          <property name="value"><number>0</number></property>
+          <property name="textVisible"><bool>false</bool></property>
+         </widget>
+        </item>
+       </layout>
       </item>
-      <item row="3" column="0"><widget class="QLabel" name="dataBitsLabel"><property name="text"><string>数据位</string></property></widget></item>
-      <item row="3" column="1">
-       <widget class="QComboBox" name="dataBitsComboBox">
-        <item><property name="text"><string>7</string></property><property name="userData"><string notr="true">7</string></property></item>
-        <item><property name="text"><string>8</string></property><property name="userData"><string notr="true">8</string></property></item>
+      <item>
+       <widget class="QLabel" name="discoveryStatusLabel">
+        <property name="text"><string>自动搜索使用当前 PLC 站号</string></property>
+        <property name="wordWrap"><bool>true</bool></property>
        </widget>
       </item>
-      <item row="4" column="0"><widget class="QLabel" name="parityLabel"><property name="text"><string>校验方式</string></property></widget></item>
-      <item row="4" column="1">
-       <widget class="QComboBox" name="parityComboBox">
-        <item><property name="text"><string>无校验</string></property><property name="userData"><string notr="true">0</string></property></item>
-        <item><property name="text"><string>奇校验</string></property><property name="userData"><string notr="true">3</string></property></item>
-        <item><property name="text"><string>偶校验</string></property><property name="userData"><string notr="true">2</string></property></item>
-       </widget>
-      </item>
-      <item row="5" column="0"><widget class="QLabel" name="stopBitsLabel"><property name="text"><string>停止位</string></property></widget></item>
-      <item row="5" column="1">
-       <widget class="QComboBox" name="stopBitsComboBox">
-        <item><property name="text"><string>1</string></property><property name="userData"><string notr="true">1</string></property></item>
-        <item><property name="text"><string>2</string></property><property name="userData"><string notr="true">2</string></property></item>
-       </widget>
+      <item>
+       <layout class="QFormLayout" name="serialFormLayout">
+        <property name="fieldGrowthPolicy"><enum>QFormLayout::AllNonFixedFieldsGrow</enum></property>
+        <item row="0" column="0"><widget class="QLabel" name="serialPortLabel"><property name="text"><string>端口</string></property></widget></item>
+        <item row="0" column="1">
+         <layout class="QHBoxLayout" name="serialPortEditorLayout">
+          <item>
+           <widget class="QComboBox" name="serialPortComboBox">
+            <property name="editable"><bool>true</bool></property>
+            <property name="placeholderText"><string>选择或输入 COM 端口</string></property>
+           </widget>
+          </item>
+          <item>
+           <widget class="QToolButton" name="refreshPortsButton">
+            <property name="minimumSize"><size><width>28</width><height>28</height></size></property>
+            <property name="maximumSize"><size><width>28</width><height>28</height></size></property>
+            <property name="toolTip"><string>刷新串口</string></property>
+            <property name="accessibleName"><string>刷新串口</string></property>
+            <property name="autoRaise"><bool>true</bool></property>
+           </widget>
+          </item>
+         </layout>
+        </item>
+        <item row="1" column="0"><widget class="QLabel" name="serverAddressLabel"><property name="text"><string>PLC 站号</string></property></widget></item>
+        <item row="1" column="1"><widget class="QSpinBox" name="serverAddressSpinBox"><property name="minimum"><number>1</number></property><property name="maximum"><number>247</number></property></widget></item>
+        <item row="2" column="0"><widget class="QLabel" name="baudRateLabel"><property name="text"><string>波特率</string></property></widget></item>
+        <item row="2" column="1">
+         <widget class="QComboBox" name="baudRateComboBox">
+          <item><property name="text"><string>9600</string></property><property name="userData"><string notr="true">9600</string></property></item>
+          <item><property name="text"><string>19200</string></property><property name="userData"><string notr="true">19200</string></property></item>
+          <item><property name="text"><string>38400</string></property><property name="userData"><string notr="true">38400</string></property></item>
+          <item><property name="text"><string>57600</string></property><property name="userData"><string notr="true">57600</string></property></item>
+          <item><property name="text"><string>115200</string></property><property name="userData"><string notr="true">115200</string></property></item>
+         </widget>
+        </item>
+        <item row="3" column="0"><widget class="QLabel" name="dataBitsLabel"><property name="text"><string>数据位</string></property></widget></item>
+        <item row="3" column="1">
+         <widget class="QComboBox" name="dataBitsComboBox">
+          <item><property name="text"><string>7</string></property><property name="userData"><string notr="true">7</string></property></item>
+          <item><property name="text"><string>8</string></property><property name="userData"><string notr="true">8</string></property></item>
+         </widget>
+        </item>
+        <item row="4" column="0"><widget class="QLabel" name="parityLabel"><property name="text"><string>校验方式</string></property></widget></item>
+        <item row="4" column="1">
+         <widget class="QComboBox" name="parityComboBox">
+          <item><property name="text"><string>无校验</string></property><property name="userData"><string notr="true">0</string></property></item>
+          <item><property name="text"><string>奇校验</string></property><property name="userData"><string notr="true">3</string></property></item>
+          <item><property name="text"><string>偶校验</string></property><property name="userData"><string notr="true">2</string></property></item>
+         </widget>
+        </item>
+        <item row="5" column="0"><widget class="QLabel" name="stopBitsLabel"><property name="text"><string>停止位</string></property></widget></item>
+        <item row="5" column="1">
+         <widget class="QComboBox" name="stopBitsComboBox">
+          <item><property name="text"><string>1</string></property><property name="userData"><string notr="true">1</string></property></item>
+          <item><property name="text"><string>2</string></property><property name="userData"><string notr="true">2</string></property></item>
+         </widget>
+        </item>
+       </layout>
       </item>
      </layout>
     </widget>

app/tests/plc_connection_dialog_tests.cpp

@@ -0,0 +1,203 @@
+#include "services/plc_discovery_gateway.h"
+#include "support/test_support.h"
+#include "ui/plc_connection_dialog.h"
+
+#include <QApplication>
+#include <QComboBox>
+#include <QCoreApplication>
+#include <QEventLoop>
+#include <QLabel>
+#include <QProgressBar>
+#include <QPushButton>
+#include <QToolButton>
+
+#include <functional>
+#include <iostream>
+#include <stdexcept>
+#include <utility>
+
+namespace {
+
+using TestSupport::require;
+
+class FakePlcDiscoveryGateway final : public PlcDiscoveryGateway
+{
+public:
+    PlcCommunicationResult startDiscovery(
+        const PlcSerialConfiguration &preferred) override
+    {
+        ++start_count;
+        last_preferred = preferred;
+        discovering = true;
+        return {true, {}};
+    }
+
+    void cancelDiscovery() override
+    {
+        if (!discovering)
+        {
+            return;
+        }
+        ++cancel_count;
+        discovering = false;
+        if (finished_callback)
+        {
+            finished_callback({false, true, {}, {}});
+        }
+    }
+
+    bool isDiscovering() const override
+    {
+        return discovering;
+    }
+
+    void setCallbacks(
+        std::function<void(const PlcDiscoveryProgress &)> progress_changed,
+        std::function<void(const PlcDiscoveryOutcome &)> discovery_finished) override
+    {
+        progress_callback = std::move(progress_changed);
+        finished_callback = std::move(discovery_finished);
+    }
+
+    void reportProgress(
+        const PlcSerialConfiguration &candidate,
+        std::size_t current,
+        std::size_t total)
+    {
+        if (progress_callback)
+        {
+            progress_callback({candidate, current, total});
+        }
+    }
+
+    void reportFound(const PlcSerialConfiguration &configuration)
+    {
+        discovering = false;
+        if (finished_callback)
+        {
+            finished_callback({true, false, configuration, "found"});
+        }
+    }
+
+    bool discovering = false;
+    int start_count = 0;
+    int cancel_count = 0;
+    PlcSerialConfiguration last_preferred;
+    std::function<void(const PlcDiscoveryProgress &)> progress_callback;
+    std::function<void(const PlcDiscoveryOutcome &)> finished_callback;
+};
+
+void testDiscoveryFindsAndAcceptsConfiguration()
+{
+    FakePlcDiscoveryGateway gateway;
+    PlcSerialConfiguration initial;
+    initial.portName = "COM1";
+    int prepare_count = 0;
+    PlcConnectionDialog dialog(
+        initial, gateway, [&prepare_count] { ++prepare_count; });
+
+    QPushButton *search_button = dialog.findChild<QPushButton *>("autoSearchButton");
+    QProgressBar *progress_bar = dialog.findChild<QProgressBar *>(
+        "discoveryProgressBar");
+    QLabel *status_label = dialog.findChild<QLabel *>("discoveryStatusLabel");
+    require(search_button != nullptr && progress_bar != nullptr
+                && status_label != nullptr,
+            "PLC dialog must expose automatic discovery controls");
+
+    search_button->click();
+    require(prepare_count == 1 && gateway.start_count == 1 && gateway.discovering,
+            "automatic discovery must release the formal connection and start once");
+    require(search_button->text() == QStringLiteral("停止搜索")
+                && !progress_bar->isHidden(),
+            "the dialog must show searchable progress and a stop command");
+
+    PlcSerialConfiguration found = initial;
+    found.portName = "COM3";
+    found.serverAddress = 1;
+    found.baudRate = 19200;
+    found.dataBits = 8;
+    found.parity = 0;
+    found.stopBits = 1;
+    gateway.reportProgress(found, 4, 180);
+    require(progress_bar->maximum() == 180 && progress_bar->value() == 4
+                && status_label->text().contains(QStringLiteral("COM3"))
+                && status_label->text().contains(QStringLiteral("8N1")),
+            "discovery progress must identify the active port and serial frame");
+
+    gateway.reportFound(found);
+    QCoreApplication::processEvents(QEventLoop::AllEvents);
+    const PlcSerialConfiguration selected = dialog.configuration();
+    require(dialog.result() == QDialog::Accepted,
+            "a successful discovery must automatically accept the dialog");
+    require(selected.portName == found.portName
+                && selected.serverAddress == found.serverAddress
+                && selected.baudRate == found.baudRate
+                && selected.dataBits == found.dataBits
+                && selected.parity == found.parity
+                && selected.stopBits == found.stopBits,
+            "a successful discovery must copy every detected serial parameter");
+}
+
+void testDiscoveryCanBeCancelled()
+{
+    FakePlcDiscoveryGateway gateway;
+    PlcSerialConfiguration initial;
+    initial.portName = "COM1";
+    PlcConnectionDialog dialog(initial, gateway, [] {});
+    QPushButton *search_button = dialog.findChild<QPushButton *>("autoSearchButton");
+    QLabel *status_label = dialog.findChild<QLabel *>("discoveryStatusLabel");
+
+    search_button->click();
+    search_button->click();
+    require(gateway.cancel_count == 1 && !gateway.discovering,
+            "the stop command must cancel the active discovery");
+    require(search_button->isEnabled()
+                && search_button->text() == QStringLiteral("自动搜索")
+                && status_label->text() == QStringLiteral("已停止自动搜索"),
+            "the dialog must return to an editable state after cancellation");
+}
+
+void testPortRefreshRemovesUnavailableSelection()
+{
+    FakePlcDiscoveryGateway gateway;
+    PlcSerialConfiguration initial;
+    initial.portName = "COM_STALE_TEST_999";
+    PlcConnectionDialog dialog(initial, gateway, [] {});
+    QComboBox *port_combo = dialog.findChild<QComboBox *>("serialPortComboBox");
+    QToolButton *refresh_button = dialog.findChild<QToolButton *>(
+        "refreshPortsButton");
+    require(port_combo != nullptr && refresh_button != nullptr,
+            "PLC dialog must expose a serial port refresh command");
+    require(port_combo->findText(QString::fromLatin1(initial.portName.c_str())) < 0,
+            "opening the dialog must not restore an unavailable saved port");
+
+    const QString stale_port = QStringLiteral("COM_STALE_TEST_998");
+    port_combo->addItem(stale_port);
+    port_combo->setCurrentText(stale_port);
+    refresh_button->click();
+    require(port_combo->findText(stale_port) < 0
+                && port_combo->currentText() != stale_port,
+            "refreshing ports must remove an unplugged or unavailable selection");
+}
+
+} // namespace
+
+int main(int argc, char *argv[])
+{
+    qputenv("QT_QPA_PLATFORM", QByteArrayLiteral("offscreen"));
+    QApplication application(argc, argv);
+    try
+    {
+        testDiscoveryFindsAndAcceptsConfiguration();
+        testDiscoveryCanBeCancelled();
+        testPortRefreshRemovesUnavailableSelection();
+    }
+    catch (const std::exception &error)
+    {
+        std::cerr << "PLC connection dialog tests failed: "
+                  << error.what() << '\n';
+        return 1;
+    }
+    std::cout << "PLC connection dialog tests passed\n";
+    return 0;
+}

app/tests/plc_connection_dialog_tests.pro

@@ -0,0 +1,18 @@
+include(pri/test_defaults.pri)
+
+TARGET = plc_connection_dialog_tests
+QT += core gui widgets serialport
+CONFIG += testcase
+
+SOURCES += \
+    plc_connection_dialog_tests.cpp \
+    ../src/ui/plc_connection_dialog.cpp
+
+HEADERS += \
+    ../src/services/plc_communication_gateway.h \
+    ../src/services/plc_discovery_gateway.h \
+    ../src/ui/plc_connection_dialog.h \
+    support/test_support.h
+
+FORMS += \
+    ../src/ui/plc_connection_dialog.ui

app/tests/plc_runtime_tests.cpp

@@ -8,12 +8,15 @@
 #include "domain/virtual_register_repository.h"
 #include "services/offline_simulation_service.h"
 #include "services/plc_communication_gateway.h"
+#include "services/plc_discovery_gateway.h"
 #include "services/project_service.h"
 #include "services/runtime_mode_service.h"
 
 #include <functional>
 #include <iostream>
+#include <set>
 #include <stdexcept>
+#include <tuple>
 #include <utility>
 
 namespace {
@@ -330,6 +333,72 @@ void testPlcConfigurationBoundaries()
             "a response timeout of 100 ms must be accepted");
 }
 
+void testPlcDiscoveryCandidatePriorityAndCoverage()
+{
+    PlcSerialConfiguration preferred;
+    preferred.portName = "COM3";
+    preferred.serverAddress = 17;
+    preferred.baudRate = 38400;
+    preferred.dataBits = 7;
+    preferred.parity = 3;
+    preferred.stopBits = 2;
+    preferred.responseTimeoutMs = 1500;
+    preferred.retries = 4;
+    preferred.pollIntervalMs = 350;
+
+    const std::vector<PlcSerialConfiguration> candidates =
+        buildPlcDiscoveryCandidates(
+            preferred, {"COM1", "COM2", "COM3", "COM2", ""});
+    require(candidates.size() == 180U,
+            "discovery must cover 60 serial settings on every unique available port");
+    require(candidates.front().portName == "COM3"
+                && candidates.front().serverAddress == 17
+                && candidates.front().baudRate == 38400
+                && candidates.front().dataBits == 7
+                && candidates.front().parity == 3
+                && candidates.front().stopBits == 2,
+            "discovery must try the complete current configuration first");
+    require(candidates.at(1).portName == "COM1"
+                && candidates.at(2).portName == "COM2",
+            "the preferred port must be first without dropping other ports");
+
+    std::set<std::tuple<std::string, int, int, int, int>> unique_candidates;
+    bool contains_standard_8e1 = false;
+    bool contains_full_supported_edge = false;
+    for (const PlcSerialConfiguration &candidate : candidates)
+    {
+        require(candidate.serverAddress == preferred.serverAddress
+                    && candidate.responseTimeoutMs == preferred.responseTimeoutMs
+                    && candidate.retries == preferred.retries
+                    && candidate.pollIntervalMs == preferred.pollIntervalMs,
+                "discovery must preserve the selected station and normal timing settings");
+        unique_candidates.emplace(
+            candidate.portName,
+            candidate.baudRate,
+            candidate.dataBits,
+            candidate.parity,
+            candidate.stopBits);
+        contains_standard_8e1 = contains_standard_8e1
+            || (candidate.portName == "COM2"
+                && candidate.baudRate == 9600
+                && candidate.dataBits == 8
+                && candidate.parity == 2
+                && candidate.stopBits == 1);
+        contains_full_supported_edge = contains_full_supported_edge
+            || (candidate.portName == "COM1"
+                && candidate.baudRate == 115200
+                && candidate.dataBits == 7
+                && candidate.parity == 0
+                && candidate.stopBits == 2);
+    }
+    require(unique_candidates.size() == candidates.size(),
+            "discovery candidates must not contain duplicate serial settings");
+    require(contains_standard_8e1 && contains_full_supported_edge,
+            "discovery must cover common settings and every supported boundary");
+    require(buildPlcDiscoveryCandidates(preferred, {}).empty(),
+            "discovery must stop immediately when no serial port is available");
+}
+
 void testPlcPollQuantityBoundaries()
 {
     PlcRegisterRepository repository;
@@ -374,6 +443,7 @@ int main()
         testRuntimeFaultRevokesOnlineReadinessAndAllowsReconnect();
         testPlcCommunicationErrorClassification();
         testPlcConfigurationBoundaries();
+        testPlcDiscoveryCandidatePriorityAndCoverage();
         testPlcPollQuantityBoundaries();
     }
     catch (const std::exception &error)

app/tests/pri/test_layers.pri

@@ -104,10 +104,12 @@ SERVICE_OFFLINE_HEADERS = \
     ../src/services/offline_simulation_service.h
 
 SERVICE_RUNTIME_SOURCES = \
-    ../src/services/runtime_mode_service.cpp
+    ../src/services/runtime_mode_service.cpp \
+    ../src/services/plc_discovery_gateway.cpp
 
 SERVICE_RUNTIME_HEADERS = \
-    ../src/services/runtime_mode_service.h
+    ../src/services/runtime_mode_service.h \
+    ../src/services/plc_discovery_gateway.h
 
 SERVICE_MONITOR_SOURCES = \
     ../src/services/register_monitor_service.cpp \
@@ -126,9 +128,11 @@ INFRASTRUCTURE_JSON_HEADERS = \
 INFRASTRUCTURE_PLC_SOURCES = \
     ../src/infrastructure/plc_communication_error_classifier.cpp \
     ../src/infrastructure/plc_register_repository.cpp \
-    ../src/infrastructure/plc_communication_service.cpp
+    ../src/infrastructure/plc_communication_service.cpp \
+    ../src/infrastructure/plc_discovery_service.cpp
 
 INFRASTRUCTURE_PLC_HEADERS = \
     ../src/infrastructure/plc_communication_error_classifier.h \
     ../src/infrastructure/plc_register_repository.h \
-    ../src/infrastructure/plc_communication_service.h
+    ../src/infrastructure/plc_communication_service.h \
+    ../src/infrastructure/plc_discovery_service.h

app/tests/tests.pro

@@ -12,6 +12,7 @@ SUBDIRS += \
     register_monitor \
     runtime_mode \
     runtime_panel_controller \
+    plc_connection_dialog \
     plc_runtime
 
 domain.file = domain_tests.pro
@@ -23,4 +24,5 @@ project_management.file = project_management_tests.pro
 register_monitor.file = register_monitor_service_tests.pro
 runtime_mode.file = runtime_mode_service_tests.pro
 runtime_panel_controller.file = runtime_panel_controller_tests.pro
+plc_connection_dialog.file = plc_connection_dialog_tests.pro
 plc_runtime.file = plc_runtime_tests.pro