实现& # 39;读者# 39;去接球块

本文关键字：实现 读者 | 更新日期: 2023-09-27 18:13:20

try
{
    sqlTran = conn.BeginTransaction();
    String tblAuto = "Select * from tblAuto_Num where Company_Code='Comp'AND Module='WSS' AND Sub_Module='SVS' AND Doc_Type='ORD'; ";
    SqlCommand cmd = new SqlCommand(tblAuto, conn);
    SqlDataReader reader = cmd.ExecuteReader();
    while (reader.Read())
    {  
    }           
    reader.Close();
    Label1.Text = "ttt";
    sqlTran.Commit();
    conn.Close();
}
catch (Exception ex)
{
    if (sqlTran != null) sqlTran.Rollback();
    Label1.Text = ex.toString();
}

当我实现SqlDataReader reader = cmd.ExecuteReader();时，它就会进入catch块。有人能解释一下原因吗?

这是错误信息:

System.InvalidOperationException: ExecuteReader requires the command to have a transaction when the connection assigned to the command is in a pending local transaction. The Transaction property of the command has not been initialized. 
at System.Data.SqlClient.SqlCommand.ValidateCommand(String method, Boolean async) 
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite) 
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method) 
at System.Data.SqlClient.SqlCommand.ExecuteReader() at TicketApp.Default.ButtonAppointment_Click(Object sender, EventArgs e) 
in c:'Users'Farhad'Documents'Visual Studio 2013'Projects'TicketApp'TicketApp'Default.aspx.cs:line 29

实现& # 39;读者# 39;去接球块

使用使用的试试. .catch当使用IDisposable时:

using (var sqlTran = conn.BeginTransaction()) {
  // Format out SQL to be more readable
  String tblAuto = 
    @"select * 
        from tblAuto_Num 
       where Company_Code = 'Comp' and 
             Module = 'WSS' and 
             Sub_Module = 'SVS' and 
             Doc_Type='ORD'; ";
  try {
    using (SqlCommand cmd = new SqlCommand(tblAuto, conn)) {
      cmd.Transaction = sqlTran; // <- Do not forget this
      using (SqlDataReader reader = cmd.ExecuteReader()) {
        while (reader.Read()) {
          ...
        }
      } 
    }
    sqlTran.Commit();
  }
  catch (Exception) {
    try {
      sqlTran.Rollback();
      Label1.Text = "bbb";
      throw; // <- When catch Exception (base class)  do not forget to throw
    } 
    catch (Exception) {
      // when rollback can't be performed
      throw;
    }
  }
}
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