使用反射获取枚举的自定义属性Attribute及其他使用方式

2012-02-07 13:02 ※森林小居※ 阅读(2347) 评论(2) 编辑收藏举报

自定义Attribue:ImgAttribute

[AttributeUsage(AttributeTargets.All, Inherited = false, AllowMultiple = true)]
  sealed class ImgAttribute : Attribute
  {
      readonly string imgUrl;
   
      public  ImgAttribute(string imgUrl)
      {
          this.imgUrl = imgUrl;
      }
     /// <summary>
     /// 图片地址
     /// </summary>
     public string ImgUrl
     {
         get { return imgUrl; }
     }
 }

使用此属性的枚举：

/// <summary>
 /// 交通方式
 /// </summary>
 public enum TransportType
 {
     [Img("/images/Airplane.jpg")]
     飞机=1,
    [Img("/images/bus.gif")]
     汽车=2,
    [Img("/images/Train.jpg")]
    火车=3,
    [Img("/images/Ship.jpg")]
    轮船=4,
    [Img("/images/Foot.jpg")]
    步行=5,
    [Img("/images/Bike.jpg")]
   自行车=6
}

使用反射获取属性值：

/// <summary>
/// 获取交通方式枚举的属性值（交通方式的图片地址）
/// </summary>
/// <param name="ttype"></param>
/// <returns></returns>
public static object getAttribute(TransportType ttype)
{
    Type t = typeof(TransportType);
    FieldInfo[] info = t.GetFields();
   for (int i = 0; i < info.Length; i++)
    {
        if (info[i].Name == ttype.ToString())
        {
            var att = info[i].GetCustomAttributes(false);
            foreach (Attribute a in att)
            {
                if (a is ImgAttribute)
                {
                    return ((ImgAttribute)a).ImgUrl;
                }
            }
            break;
        }
    }
    return null;
}

将指定的枚举类型转换成List方式代码如下：

/// <summary>
        /// 将指定枚举类型转换成List，用来绑定ListControl
        /// </summary>
        /// <param name="EnumType">枚举类型</param>
        /// <param name="SelectFirst">是否需要第一项选择</param>
        /// <param name="FirstItem">第一项选择的内容，0设置为Text,1设置为Value，多余的不设。可以为空或不传</param>
        /// <returns></returns>
        public static List<ListItem> ConvertEnumToListItems(Type EnumType, bool SelectFirst, params string[] FirstItem)
        {
            if (EnumType.IsEnum == false) { return null; }
            List<ListItem> ListResult = new List<ListItem>();
            Type TypeDescription = typeof(DescriptionAttribute);
            FieldInfo[] Fields = EnumType.GetFields();
            string StrText = string.Empty;
            string StrValue = string.Empty;
            foreach (FieldInfo Field in Fields)
            {
                if (Field.IsSpecialName) continue;
                StrValue = Field.GetRawConstantValue().ToString();
                object[] arr = Field.GetCustomAttributes(TypeDescription, true);
                if (arr.Length > 0)
                {
                    StrText = (arr[0] as DescriptionAttribute).Description;
                }
                else
                {
                    StrText = Field.Name;
                }
 
                ListResult.Add(new ListItem(StrText,StrValue));
            }
            if (SelectFirst)
            {
                if (FirstItem != null && FirstItem.Length > 1)
                {
                    ListResult.Insert(0, new ListItem(FirstItem[0], FirstItem[1]));
                }
                else if (FirstItem != null && FirstItem.Length == 1)
                {
                    ListResult.Insert(0, new ListItem(FirstItem[0], "0"));
                }
                else
                {
                    ListResult.Insert(0, new ListItem("请选择", "0"));
                }
            }
            return ListResult;
        }

public class ListItem
    {
        public ListItem() { }
        public ListItem(string EnumName, string EnumValue)
        {
            this.EnumName = EnumName;
            this.EnumValue = EnumValue;
        }
 
        public string EnumName
        {
            get;
            set;
        }
        public string EnumValue
        {
            get;
            set;
        }
    }