linq to sql 扩展方法-白红宇

linq to sql 扩展方法

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发布时间：2019-06-14

本文共 3762 字，大约阅读时间需要 12 分钟。

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1、DataContext扩展方法

public static class DataContextExentions    {        ///         /// 打开连接        /// 
        ///         private static void OpenConnection(this DataContext dataContext)        {            if (dataContext.Connection.State == ConnectionState.Closed)            {                dataContext.Connection.Open();            }        }        ///         /// 扩展ExecuteQuery方法         /// 
        /// 
              ///         ///         ///         /// 
              public static List
      
        ExecuteQuery
       
        (this DataContext dataContext, IQueryable query, bool withNoLock)        {            DbCommand command = dataContext.GetCommand(query, withNoLock);            dataContext.OpenConnection();            using (DbDataReader reader = command.ExecuteReader())            {                return dataContext.Translate
        
         (reader).ToList();            }        }        /// 
                 /// 扩展ExecuteQuery方法2        /// 
        /// 
                 /// 
                 /// 
                 /// 
                 /// 
                 public static List
         
           ExecuteQuery
          
           (this DataContext dataContext, IQueryable query)        {            DbCommand command = dataContext.GetCommand(query);            dataContext.OpenConnection();            using (DbDataReader reader = command.ExecuteReader())            {                return dataContext.Translate
           
            (reader).ToList(); } } /// 
             /// 扩展GetCommend方法，允许设置WithNoLick /// 
 /// 
             /// 
             /// 
             /// 
             private static SqlCommand GetCommand(this DataContext dataContext, IQueryable query, bool withNoLock) { SqlCommand command = (SqlCommand)dataContext.GetCommand(query); if (withNoLock) { command.CommandText = AddWithNoLock(command.CommandText); } return command; } /// 
             /// 将Sql语句修改为with nolock /// 
 /// 
             /// 
             private static string AddWithNoLock(string cmdText) { IEnumerable
            
              matches = s_withNoLockRegex.Matches(cmdText).Cast
             
              () .OrderByDescending(m => m.Index); foreach (Match m in matches) { int splitIndex = m.Index + m.Value.Length; cmdText = cmdText.Substring(0, splitIndex) + " WITH (NOLOCK)" + cmdText.Substring(splitIndex); } return cmdText; } private static Regex s_withNoLockRegex = new Regex(@"(] AS [td+])", RegexOptions.Compiled); }}

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2、DataContext扩展方法支持分页

/// /// DataContext扩展方法/// 
public static class DataContextExtends{    ///     /// ExecuteQuery方法扩展，将对象以redader方式转换为实体    /// 
    /// 
          ///     ///     /// 
          public static List
      
        ExecuteQuery
       
        (this DataContext dataContext, IQueryable