I am using code similar to this Support / KB article to r开发者_如何学Goeturn multiple recordsets to my C# program.
But I don't want C# code to be dependant on the physical sequence of the recordsets returned, in order to do it's job.
So my question is, "Is there a way to determine which set of records from a multiplerecordset resultset am I currently processing?"
I know I could probably decipher this indirectly by looking for a unique column name or something per resultset, but I think/hope there is a better way.
P.S. I am using Visual Studio 2008 Pro & SQL Server 2008 Express Edition.
No, because the SqlDataReader
is forward only. As far as I know, the best you can do is open the reader with KeyInfo
and inspect the schema data table created with the reader's GetSchemaTable
method (or just inspect the fields, which is easier, but less reliable).
I spent a couple of days on this. I ended up just living with the physical order dependency. I heavily commented both the code method and the stored procedure with !!!IMPORTANT!!!
, and included an #If...#End If
to output the result sets when needed to validate the stored procedure output.
The following code snippet may help you.
Helpful Code
Dim fContainsNextResult As Boolean
Dim oReader As DbDataReader = Nothing
oReader = Me.SelectCommand.ExecuteReader(CommandBehavior.CloseConnection Or CommandBehavior.KeyInfo)
#If DEBUG_ignore Then
'load method of data table internally advances to the next result set
'therefore, must check to see if reader is closed instead of calling next result
Do
Dim oTable As New DataTable("Table")
oTable.Load(oReader)
oTable.WriteXml("C:\" + Environment.TickCount.ToString + ".xml")
oTable.Dispose()
Loop While oReader.IsClosed = False
'must re-open the connection
Me.SelectCommand.Connection.Open()
'reload data reader
oReader = Me.SelectCommand.ExecuteReader(CommandBehavior.CloseConnection Or CommandBehavior.KeyInfo)
#End If
Do
Dim oSchemaTable As DataTable = oReader.GetSchemaTable
'!!!IMPORTANT!!! PopulateTable expects the result sets in a specific order
' Therefore, if you suddenly start getting exceptions that only a novice would make
' the stored procedure has been changed!
PopulateTable(oReader, oDatabaseTable, _includeHiddenFields)
fContainsNextResult = oReader.NextResult
Loop While fContainsNextResult
Because you're explicitly stating in which order to execute the SQL statements the results will appear in that same order. In any case if you want to programmatically determine which recordset you're processing you still have to identify some columns in the result.
精彩评论