PipelineComponent.PreExecute Method
Called after PrepareForExecute, and before PrimeOutput and ProcessInput.
Spazio dei nomi: Microsoft.SqlServer.Dts.Pipeline
Assembly : Microsoft.SqlServer.PipelineHost (in microsoft.sqlserver.pipelinehost.dll)
Sintassi
'Dichiarazione
Public Overridable Sub PreExecute
public virtual void PreExecute ()
public:
virtual void PreExecute ()
public void PreExecute ()
public function PreExecute ()
Osservazioni
Component developers should factor as much functionality into PreExecute as possible because it is called one time per component instead of one time per buffer for ProcessInput. Components should locate the indexes of its input and output columns in the PipelineBuffer by calling the FindColumnByLineageID method of the BufferManager.
Esempio
The following example shows how to locate the column indexes of the columns in the InputColumnCollection. They are stored in a local variable and then used in ProcessInput to access the columns in the PipelineBuffer.
int[] bufferColumnIndex;
public override void PreExecute()
{
IDTSInput90 input = ComponentMetaData.InputCollection[0];
bufferColumnIndex = new int[input.InputColumnCollection.Count];
for ( int x=0; x < input.InputColumnCollection.Count; x++)
{
bufferColumnIndex[x] = BufferManager.FindColumnByLineageID( input.Buffer, input.InputColumnCollection[x].LineageID);
}
}
public override void ProcessInput( int inputID, PipelineBuffer buffer )
{
if( !buffer.EndOfRowset)
{
while( buffer.NextRow() )
{
for( int x=0; x < bufferColumnIndex.Length(); x++ )
{
if( !buffer.IsNull(bufferColumnIndex[x]))
{
// TODO: Access the column data.
}
}
}
}
}
Private bufferColumnIndex As Integer()
Public Overrides Sub PreExecute()
Dim input As IDTSInput90 = ComponentMetaData.InputCollection(0)
bufferColumnIndex = New Integer(input.InputColumnCollection.Count - 1) {}
Dim x As Integer = 0
While x < input.InputColumnCollection.Count
bufferColumnIndex(x) = BufferManager.FindColumnByLineageID(input.Buffer, input.InputColumnCollection(x).LineageID)
x -= 1
End While
End Sub
Public Overrides Sub ProcessInput(ByVal inputID As Integer, ByVal buffer As PipelineBuffer)
If Not buffer.EndOfRowset Then
While buffer.NextRow
Dim x As Integer = 0
While x < bufferColumnIndex.Length
If Not buffer.IsNull(bufferColumnIndex(x)) Then
End If
x -= 1
End While
End While
End If
End Sub
Thread Safety
Any public static (Shared in Microsoft Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Piattaforme
Piattaforme di sviluppo
Per un elenco delle piattaforme supportate, vedere Requisiti hardware e software per l'Installazione di SQL Server 2005.
Piattaforme di destinazione
Per un elenco delle piattaforme supportate, vedere Requisiti hardware e software per l'Installazione di SQL Server 2005.
Vedere anche
Riferimento
PipelineComponent Class
PipelineComponent Members
Microsoft.SqlServer.Dts.Pipeline Namespace