如何使用自定义 DbDataReader 填充表值参数?

Question

根据MSDN，System.Data.SqlClient支持从DataTable、DbDataReader或IEnumerable<SqlDataRecord>对象填充表值参数。

我编写了以下代码，它使用IEnumerable<SqlDataRecord>对象填充表值参数表：

static void Main()
{       
List<int> idsToSend = ...
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();    
SqlCommand command = new SqlCommand(@"SELECT ...
FROM ... 
INNER JOIN @ids mytable ON ...", connection);
command.Parameters.Add(new SqlParameter("@ids", SqlDbType.Structured)
{
TypeName = "int_list_type",
Direction = ParameterDirection.Input,
Value = GetSqlDataRecords(idsToSend) //returns IEnumerable<SqlDataRecord> 
});
SqlDataReader reader = command.ExecuteReader();
//consume reader...
}
}

它工作得很好。

MSDN 页面说：

您还可以使用从DbDataReader派生的任何对象来流式传输行 的数据到表值参数。

我想改用自定义DbDataReader来传递行数据。像这样：

public class CustomDataReader : DbDataReader
{
public CustomDataReader(IEnumerable<int> values)
{           
}
//implementation of other abstract methods and fields required by DbDataReader
//...
}

我在初始代码示例中更改了以下行：

Value = GetSqlDataRecords(idsToSend)
=>
Value = new CustomDataReader(idsToSend)

如果我运行代码，它会在执行command.ExecuteReader()期间给我以下异常：

发生类型为"系统.不支持的异常"的未处理异常 在 System.Data 中.dll 附加信息：指定的方法不是 支持。

我在CustomDbDataReader类的所有方法和属性上都放置了一个断点：在我得到异常之前没有调用它们，所以它可能与DbDataReader的实现无关

---

编辑：这是堆栈跟踪，根据要求：

at System.Data.SqlClient.TdsParser.TdsExecuteRPC(SqlCommand cmd, _SqlRPC[] rpcArray, Int32 timeout, Boolean inSchema, SqlNotificationRequest notificationRequest, TdsParserStateObject stateObj, Boolean isCommandProc, Boolean sync, TaskCompletionSource`1 completion, Int32 startRpc, Int32 startParam)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds, Boolean describeParameterEncryptionRequest)
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 ConsoleApplication211.Program.Main() in Program.cs:line 51
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

Answer 1

你需要实现GetSchemaTable，它没有标记为抽象。

另请参阅：如何使用 DataReader GetSchemaTable 方法和 Visual C# .NET 检索列架构