.net 特性 Attribute

public sealed class RemarkAttribute : Attribute
    {
        public string Remark { get; set; }

        // 构造函数
        public RemarkAttribute(string remark)
        {
            this.Remark = remark;
        }

        /// <summary>
        /// 获取枚举备注属性
        /// </summary>
        /// <param name="_enum">枚举类参数</param>
        /// <returns>String</returns>
        public static string GetEnumRemark(Enum _enum)
        {
            string result = string.Empty;
            Type type = _enum.GetType();
            FieldInfo fd = type.GetField(_enum.ToString());
            if (fd != null)
            {
                object[] attrs = fd.GetCustomAttributes(typeof(RemarkAttribute), false);
                foreach (RemarkAttribute attr in attrs)
                    result = attr.Remark;
            }
            return result;
        }

        /// <summary>
        /// 下拉列表绑定枚举属性值
        /// </summary>
        /// <param name="ddl">DropDownList</param>
        /// <param name="_enum">枚举</param>
        public static void DataBind(DropDownList ddl, Type _enum)
        {
            List<StructRemark> list = GetStructRemarkList(_enum);
            foreach (StructRemark item in list)
            {
                ListItem listItem = new ListItem();
                listItem = new ListItem(item.FieldText, item.FieldValue.ToString());
                ddl.Items.Add(listItem);
            }
        }

        /// <summary>
        /// 下拉列表绑定枚举属性值(有默认项)
        /// </summary>
        /// <param name="ddl">DropDownList</param>
        /// <param name="_enum">枚举</param>
        public static void DataBind(DropDownList ddl, Type _enum, string firstValue, string firstText)
        {
            List<StructRemark> list = GetStructRemarkList(_enum);
            foreach (StructRemark item in list)
            {
                ListItem listItem = new ListItem();
                listItem = new ListItem(item.FieldText, item.FieldValue.ToString());
                ddl.Items.Add(listItem);
            }
            ddl.Items.Insert(0, new ListItem(firstText, firstValue));
        }

        /// <summary>
        /// 把枚举转换成DataTable
        /// </summary>
        /// <param name="_enum">枚举</param>
        public static DataTable GetDataTable(Type _enum)
        {
            DataTable dt = new DataTable();
            DataColumn dc = null;
            dc = dt.Columns.Add("Value", Type.GetType("System.Int32"));
            dc = dt.Columns.Add("Text", Type.GetType("System.String"));
            DataRow dr = null;
            List<StructRemark> list = GetStructRemarkList(_enum);
            foreach (StructRemark item in list)
            {
                dr = dt.NewRow();
                dr["Value"] = item.FieldValue;
                dr["Text"] = item.FieldText;
                dt.Rows.Add(dr);
            }
            return dt;
        }

        /// <summary>
        /// 获取枚举备注属性集
        /// </summary>
        /// <param name="_enum">枚举</param>
        /// <returns>枚举属性结构</returns>
        public static List<StructRemark> GetStructRemarkList(Type _enum)
        {
            List<StructRemark> list = new List<StructRemark>();
            StructRemark model = new StructRemark();
            foreach (int value in Enum.GetValues(_enum))
            {
                model.FieldValue = value;
                FieldInfo fd = _enum.GetField(Enum.GetName(_enum, value));
                string name = string.Empty;
                if (fd == null)
                    name = "";
                object[] attrs = fd.GetCustomAttributes(typeof(RemarkAttribute), false);
                foreach (RemarkAttribute attr in attrs)
                {
                    name = attr.Remark;
                }
                model.FieldText = name;
                list.Add(model);
            }
            return list;
        }

        /// <summary>
        /// 枚举属性结构
        /// </summary>
        public struct StructRemark
        {
            public int FieldValue;//值
            public string FieldText;//键
        }
    }

 

特性 Attribute：

公共语言运行时允许添加类似关键字的描述声明，叫做attributes, 它对程序中的元素进行标注，如类型、字段、方法和属性等。Attributes和Microsoft .NET Framework文件的元数据保存在一起，可以用来向运行时描述你的代码，或者在程序运行的时候影响应用程序的行为。

我们简单的总结为：定制特性attribute，本质上是一个类，其为目标元素提供关联附加信息，并在运行期以反射的方式来获取附加信息。具体的特性实现方法，在接下来的讨论中继续深入。

自定义特性     public sealed class RemarkAttribute : Attribute  以Attribute  Remark则表示你的特性