using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Markup;
using System;
using System.Reflection;
namespace ModbusDemo.Extension
{
    /// <summary>
    /// 此处代码是复制粘贴，用来让枚举类型绑定到下拉框上
    /// </summary>
    class EnumBindingSourceExtension : MarkupExtension
    {
        //枚举字段
        private Type _enumType;

        public Type EnumType
        {
            get => _enumType;
            set
            {
                if (value != _enumType)
                {
                    if (value != null)
                    {
                        Type enumType = Nullable.GetUnderlyingType(value) ?? value;
                        if (!enumType.IsEnum)
                            throw new ArgumentException("Type must be for an Enum.");
                    }

                    _enumType = value;
                }
            }
        }

        public EnumBindingSourceExtension() { }

        public EnumBindingSourceExtension(Type enumType)
        {
            EnumType = enumType;
        }
        /// <summary>
        /// 将枚举转换为数组，返回出去
        /// 可以绑定可空枚举
        /// </summary>
        /// <param name="serviceProvider">xmal上下文</param>
        /// <returns></returns>
        /// <exception cref="InvalidOperationException"></exception>
        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            if (_enumType == null)
                throw new InvalidOperationException("The EnumType must be specified.");

            var actualEnumType = Nullable.GetUnderlyingType(_enumType) ?? _enumType;
            var enumValues = Enum.GetValues(actualEnumType);

            if (actualEnumType == _enumType)
                return enumValues;

            var tempArray = Array.CreateInstance(actualEnumType, enumValues.Length + 1);
            enumValues.CopyTo(tempArray, 1);
            return tempArray;
        }
    }
}