using System;
using System.ComponentModel;
using System.Reflection;
 
/// <summary>
/// 描述特性的讀取擴展類
/// </summary>
public static class DescriptionExtension
{
    /// <summary>
    /// 獲取枚舉的描述信息
    /// </summary>
    public static string GetDescription(this Enum em)
    {
        Type type = em.GetType();
        FieldInfo fd = type.GetField(em.ToString());
        string des = fd.GetDescription();
        return des;
    }



    /// <summary>
    /// 獲取屬性的描述信息
    /// </summary>
    public static string GetDescription(this Type type, string proName)
    {
        PropertyInfo pro = type.GetProperty(proName);
        string des = proName;
        if (pro != null)
        {
            des = pro.GetDescription();
        }
        return des;
    }



    /// <summary>
    /// 獲取屬性的描述信息
    /// </summary>
    public static string GetDescription(this MemberInfo info)
    {
        var attrs = (DescriptionAttribute[])info.GetCustomAttributes(typeof(DescriptionAttribute), false);
        string des = info.Name;
        foreach (DescriptionAttribute attr in attrs)
        {
            des = attr.Description;
        }
        return des;
    }
}

[Description("測試枚舉名")]
enum TestEnum 
{
    [Description("測試")]
    Test1 
}

[Description("測試類名")]
class TestClass
{
    [Description("測試class")]
    public int Test1 { get; set; }
}

//獲取枚舉類型的描述特性
string str1 = typeof(TestEnum).GetDescription();

//獲取枚舉值的描述特性
string str2 =TestEnum.Test1.GetDescription();
str2 = typeof(TestEnum).GetDescription(nameof(TestEnum.Test1));
str2 = typeof(TestEnum).GetDescription(TestEnum.Test1.ToString());

//獲取類的描述特性
string str3 = typeof(TestClass).GetDescription();

//獲取屬性的描述特性（也可以反射遍歷屬性列表）
string str4 = typeof(TestClass).GetDescription();
TestClass test = new TestClass();
str4 = typeof(TestClass).GetDescription(nameof(test.Test1));

/// <summary>
/// 擴展方法，獲得枚舉的Description
/// </summary>
/// <param name="value">枚舉值</param>
/// <param name="nameInstead">當枚舉值沒有定義DescriptionAttribute，是否使用枚舉名代替，默認是使用</param>
/// <returns>枚舉的Description</returns>
public static string GetDescription(this Enum value, Boolean nameInstead = true)
{
    Type type = value.GetType();
    string name = Enum.GetName(type, value);
    if (name == null)
    {
        return null;
    }
  
    FieldInfo field = type.GetField(name);
    DescriptionAttribute attribute = System.Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute)) as DescriptionAttribute;
  
    if (attribute == null && nameInstead == true)
    {
        return name;
    }
    return attribute?.Description;
}

public enum ModuleType
 {
     /// <summary>
     /// 中國
     /// </summary>
     [Description("中國")]
     ZH = 1,
     /// <summary>
     /// 美國
     /// </summary>
     [Description("美國")]
     MG = 2
 }