使用继承的自定义IDataReader从IDbCommand读取

Question

我已经使自定义类继承IDataReader并已成功实现自定义ServerWriter sqlBulkCopy与使用C#对象而不是的自定义类DataTable.

事实证明,这是我所怀疑的更有效的方法.

现在我正在努力Read,我有一些问题

这是IDataReader:

// get Server Data Table Object IDataReader
public class GetSDTOIDataReaderM : IDataReader
{
   //private IEnumerator<MyTestObject> enumerator = null;

   public MySqlDbTableObject.Raw.SqlDbTableM propSqlTbl { get; set; }

   // implementing relevant GetValue(), filedCount() and Read()
   // this is how I did with WriteToServer
   public bool Read()
   {
       return ++this.ReaderRowsCount < this.propSqlTbl.Table.ElementAt(0).Row.Count;
   }
}

该对象与其对应的SqlTable完全映射.

SqlCommand在我的自定义IDataReader上设置一个到ExecuteReader()没有工作,所以我尝试了 IDbCommand它然后它编译,但仍然在尝试阅读时我得到一个错误:

无法将"System.Data.SqlClient.SqlDataReader"类型的对象强制转换为"GetSDTOIDataReaderM"类型

this.propComunicator.AsGetSDTOCom().SqlCmd.Connection.Open();
//this is the line of the error
using (this.propComunicator.AsGetSDTOCom().SDTOIDataReader = (Raw.Comunicator.Raw.GetSDTOIDataReaderM)this.propComunicator.AsGetSDTOCom().SqlCmd.ExecuteReader())
{

}

写入服务器它确实有效,我怎样才能正确实现Read？

UPDATE

关于我的模块的更多信息

public class TransManSF
{
    public enum CommunicatorTypeS { Reader, Adapter, GetSDTOReaderA, SqlBcpyIDataReaderM };
    public enum DbIntreactorTypeS { TableObject, TableRowObject, Sproc, SqlCmd };
    public enum SqlCmdActionS { NotSet, SELECT, INSERT, UPDATE, DROP };
    public enum SqlCmdStrSelModeS { Single, RecentEfected, count, All, Top10, Top100, Top1000 };
    public enum SqlCmdStrSelOrderByS { NotSet = 0, Asc = 1, Desc = 2 };
    public enum SqlCmdStrSetterModeS { Single, Multi};
    public enum STDOTypeS { NotSet, ServerWriter, ServerTableGetter, ServerBiDerctional }
    public enum SprocTypeS { Sproc, TvPSrpoc }
    public enum TransExecActionTypeS { WriteToServer, GetTable }
}

public static TransMan.Raw.ComunicatorCLF.BulkCopyComSCL AsBulkCopyCom(this TransMan.Raw.ComunicatorCLF.ComunicatorM SelfCom)
{
    return (TransMan.Raw.ComunicatorCLF.BulkCopyComSCL)SelfCom;
}

virtual public void ExecuteTransaction(AppMods.DataBase.TransManSF.TransExecActionTypeS parSelectedTransType, TransManSF.SqlCmdStrSelOrderByS parExecOrderByS, int OrderByOrdinal = 0)
{
    if (parSelectedTransType == AppMods.DataBase.TransManSF.TransExecActionTypeS.WriteToServer)
        using (this.propComunicator.AsBulkCopyCom().Conn)
        {
            this.propComunicator.AsBulkCopyCom().Conn.Open();
            using (var IDRdrServerWriter = this.propComunicator.AsBulkCopyCom().ServerWriter)
            {
                var Eng = this.propExecuter.AsBulkCopyExec().Engine;
                Eng.BulkCopyTimeout = 240;
                Eng.WriteToServer(IDRdrServerWriter);

            }
            this.propComunicator.AsBulkCopyCom().Conn.Close();
        }
    else if (parSelectedTransType == AppMods.DataBase.TransManSF.TransExecActionTypeS.GetTable)
    {
        var DreaderCom = this.propComunicator.AsDReaderCom();
        using (DreaderCom.SqlCmd.Connection)
        {
            DreaderCom.SqlCmd.Connection.Open();
            using (DreaderCom.Driver = DreaderCom.SqlCmd.ExecuteReader())
            {
                if (DreaderCom.Driver.HasRows) while (DreaderCom.Driver.Read())
                    {
                        for (int i = 0; i < DreaderCom.Driver.FieldCount; i++)
                        {
                            var CurRdrColumn = DreaderCom.Driver.GetValue(i);
                            this.Table[i, 0] = CurRdrColumn;
                        }
                    }
            }
            DreaderCom.SqlCmd.Connection.Close();
        }                           
    }
}


public struct customComConfgBulkCopyA
{
      public TransManSF.CommunicatorTypeS ComType;
      public customComConfgBulkCopyA(TransManSF.CommunicatorTypeS ctrComType = TransManSF.CommunicatorTypeS.SqlBcpyIDataReaderM)
      {
          this.ComType = ctrComType;
      }
}
public sealed class BulkCopyComSCL :CustomComA
{
     public new Configurations.comunicator.customComConfgBulkCopyA Meta;
     public SqlConnection Conn { get; set; }
     public Raw.SqlBcpyIDataReaderM ServerWriter { get; set; }
}

public class SqlDbTableM : SqlDB1stTransA
{
     virtual public DbSchema.Raw.TableDictionaryA TableDict { get; set; }
     public virtual new TransMan.Raw.Configurations.SDB1stTransConfgF.SDTOMetaA Meta { get; set; }
     virtual public Raw.ColumnSetsCollM Table { get; set; }
     public override TransMan.Raw.ComunicatorCLF.ComunicatorM propComunicator
     {
         get
         {
              return base.propComunicator;
         }
         set
         {
              base.propComunicator = value;
         }
     }
     public override TransMan.Raw.Executers.ExecuterM propExecuter
     {
         get
         {
             return base.propExecuter;
         }
         set
         {
             base.propExecuter = value;
         }
     }
     public SqlDbTableM(TransManSF.STDOTypeS ctrTransType)
            : base(TransManSF.DbIntreactorTypeS.TableObject) { }
}

public sealed class GetSDTOComSCL : CustomComA
{
    public new Configurations.comunicator.customComConfgGetSDTOReaderA Meta;
    public new IDbCommand SqlCmd;
    public Raw.GetSDTOIDataReaderM SDTOIDataReader { get; set; }
}

Answer 1

简答:你不能改变返回的类型SqlCommand.ExecuteReader().

它永远是一个实例SqlDataReader.

各种方案:

1包装对你有意义的东西.

如果你走到了极端,IDbProviderFactory那就SqlConnection用自己的连接,命令和datareader类编写自己的包装.

例如,这就是Miniprofiler用于检测所有SQL请求并收集执行时间,行数等的功能.源代码

或者你可以用一些扩展方法包装读者,如下:sqlCmd.ExecuteReader().AsMyReader().我们AsMyReader()将做的是返回一个自定义IDataReader的东西,并将其委托给实际的东西SqlDataReader.

2使用现有的帮助程序库

我不太确定你在阅读内容时想要达到的目标,但在这个空间里存在着很好的库.无需提出自己的解决方案.

FastMember(Nuget)允许IDataReader在任何IEnumerable<T>或周围创建接口DataTable.它可以很容易地用作种子,SqlBulkCopy以便最大限度地插入数据.性能进入SQL Server表.

此外,为了简化执行SQL查询和解析结果,Dapper非常棒.