c#經過反射獲取類上的自定義特性

c#經過反射獲取類上的自定義特性

本文轉載：http://www.cnblogs.com/jeffwongishandsome/archive/2009/11/18/1602825.html

 

 

下面這個是筆者在之前的一個項目中用到的。當時是爲了在導出excel報表的時侯，經過自定義特性，包含一些可配置的特性在裏面。具體的操做excel不是本文重點，本文不會多作說明。下面只寫個示例，簡單說明一下如何經過反射獲取自定義特性。示例只在類和屬性上使用了自定義特性。讀者能夠按照實際的項目需求，合理使用自定義特性。

一、實現實體自定義特性，繼承自Attribute類

Code    ///<summary>     /// 自定義特性 屬性或者類可用  支持繼承     ///</summary>    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Class, Inherited =true)]     publicclass EnitityMappingAttribute : Attribute     {         privatestring tableName;         ///<summary>         /// 實體實際對應的表名         ///</summary>        publicstring TableName         {             get { return tableName; }             set { tableName = value; }         }
        privatestring columnName;         ///<summary>         /// 中文列名         ///</summary>        publicstring ColumnName         {             get { return columnName; }             set { columnName = value; }         }     }

註釋中我已經寫的很清楚，自定義特性中的屬性一個是實體實際對應的數據庫表名，一個是對應的中文列名稱。 二、在實體中使用自定義特性

Code ///<summary>     /// 會員 ，實際的表名叫MemberInfo，並非和實體名一致     ///</summary>    [EnitityMapping(TableName="MemberInfo")]     publicclass Member     {         privateint id;         [EnitityMapping(ColumnName="關鍵字")]         publicint Id         {             get { return id; }             set { id = value; }         }
        privatestring userName;         [EnitityMapping(ColumnName ="會員註冊名")]         publicstring UserName         {             get { return userName; }             set { userName = value; }         }
        privatestring realName;         [EnitityMapping(ColumnName ="會員真實名")]         publicstring RealName         {             get { return realName; }             set { realName = value; }         }
        privatebool isActive;         ///<summary>         /// 是否活躍  沒有附加自定義屬性         ///</summary>        publicbool IsActive         {             get { return isActive; }             set { isActive = value; }         }     }

三、顯示自定義特性

Code    class Program     {         ///<summary>         /// 經過反射取自定義屬性         ///</summary>         ///<typeparam name="T"></typeparam>        privatestaticvoid DisplaySelfAttribute<T>() where T:class ,new()         {             string tableName =string.Empty;             List<string> listColumnName =new List<string>();             Type objType =typeof(T);             //取屬性上的自定義特性            foreach (PropertyInfo propInfo in objType.GetProperties())             {                 object[] objAttrs = propInfo.GetCustomAttributes(typeof(EnitityMappingAttribute), true);                 if (objAttrs.Length>0)                 {                     EnitityMappingAttribute attr = objAttrs[0] as EnitityMappingAttribute;                     if (attr !=null)                     {                         listColumnName.Add(attr.ColumnName); //列名                    }                 }             }
            //取類上的自定義特性            object[] objs = objType.GetCustomAttributes(typeof(EnitityMappingAttribute), true);             foreach (object obj in objs)             {                 EnitityMappingAttribute attr = obj as EnitityMappingAttribute;                 if (attr !=null)                 {
                    tableName = attr.TableName;//表名只有獲取一次                    break;                 }             }             if (string.IsNullOrEmpty(tableName))             {                 tableName = objType.Name;             }             Console.WriteLine(string.Format("The tablename of the entity is:{0} ", tableName));             if (listColumnName.Count >0)             {                 Console.WriteLine("The columns of the table are as follows:");                 foreach (string item in listColumnName)                 {                     Console.WriteLine(item);                 }             }         }
        staticvoid Main(string[] args)         {             DisplaySelfAttribute<Member>(); //顯示結果            Console.ReadLine();         }     }