Article
10/01/2010

DTSBufferManagerClass.FindColumnByLineageID Method

Gets the location of a column in the specified IDTSBuffer100 object.

Namespace: Microsoft.SqlServer.Dts.Pipeline.Wrapper
Assembly: Microsoft.SqlServer.DTSPipelineWrap (in Microsoft.SqlServer.DTSPipelineWrap.dll)

Syntax

'Declaration
Public Overridable Function FindColumnByLineageID ( _
    hBufferType As Integer, _
    nLineageID As Integer _
) As Integer
'Usage
Dim instance As DTSBufferManagerClass
Dim hBufferType As Integer
Dim nLineageID As Integer
Dim returnValue As Integer

returnValue = instance.FindColumnByLineageID(hBufferType, _
    nLineageID)

public virtual int FindColumnByLineageID(
    int hBufferType,
    int nLineageID
)

public:
virtual int FindColumnByLineageID(
    [InAttribute] int hBufferType, 
    [InAttribute] int nLineageID
)

abstract FindColumnByLineageID : 
        hBufferType:int * 
        nLineageID:int -> int 
override FindColumnByLineageID : 
        hBufferType:int * 
        nLineageID:int -> int

public function FindColumnByLineageID(
    hBufferType : int, 
    nLineageID : int
) : int

Parameters

hBufferType
Type: System.Int32
The ID of the IDTSBuffer100 object that contains the column.

nLineageID
Type: System.Int32
The lineage ID of the column to locate in the IDTSBuffer100.

Return Value

Type: System.Int32
An Integer that indicates the location, by index, of the column in the IDTSBuffer100.

Implements

IDTSBufferManager100.FindColumnByLineageID(Int32, Int32)

Remarks

This method locates the column of an IDTSInput100 or IDTSOutput100 in the specified IDTSBuffer100. This method is necessary because an instance of a buffer contains all of the IDTSOutputColumn100 objects defined in the IDTSOutputColumnCollection100 of the components in a graph. Components cannot rely on using the index location of an output column or input column as the index of that column in a buffer row. Because of this, components must use the FindColumnByLineageID method to locate the columns in the buffer.

Examples

The following code example shows how a transformation component that does not have output columns uses FindColumnByLineageID to locate its input columns in the buffer.

int[] bufferColumnIndex;
public override void PreExecute()
{
    IDTSInput100 input = ComponentMetaData.InputCollection[0];
    bufferColumnIndex = new int[BufferManager.GetColumnCount(input.Buffer)];

    for( int col=0; col < input.InputColumnCollection.Count; col++)
    {
        IDTSInputColumn100 iCol = input.InputColumnCollection[col];
        bufferColumnIndex[col] = BufferManager.FindColumnByLineageID(input.Buffer, iCol.LineageID);
    }
}

Private bufferColumnIndex As Integer() 

Public Overloads Overrides Sub PreExecute() 
 Dim input As IDTSInput100 = ComponentMetaData.InputCollection(0) 
 bufferColumnIndex = New Integer(BufferManager.GetColumnCount(input.Buffer) - 1) {} 
 Dim col As Integer = 0 
 While col < input.InputColumnCollection.Count 
   Dim iCol As IDTSInputColumn100 = input.InputColumnCollection(col) 
   bufferColumnIndex(col) = BufferManager.FindColumnByLineageID(input.Buffer, iCol.LineageID) 
   col -= 1 
 End While 
End Sub

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