PipelineComponent.PreExecute Method

Definition

Namespace:

Microsoft.SqlServer.Dts.Pipeline

Assembly:

Microsoft.SqlServer.PipelineHost.dll

Called after PrepareForExecute(), and before PrimeOutput(Int32, Int32[], PipelineBuffer[]) and ProcessInput(Int32, PipelineBuffer).

public:
 virtual void PreExecute();

public virtual void PreExecute ();

abstract member PreExecute : unit -> unit
override this.PreExecute : unit -> unit

Public Overridable Sub PreExecute ()

Examples

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()  
{  
    IDTSInput100 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 )  
{  
    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 IDTSInput100 = 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)   
 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 Sub  

Remarks

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.