Public ReadOnly Property ColumnBegin As Integer

Dim instance As DragFillBlockCompletedEventArgs
Dim value As Integer
 
value = instance.ColumnBegin

public int ColumnBegin {get;}

private void fpSpread1DragFillBlockCompleted(object sender, FarPoint.Win.Spread.DragFillBlockCompletedEventArgs e) 
{
     fpSpread1.ActiveSheet.Columns(e.ColumnBegin).BackColor = Color.Yellow;
}

Private Sub FpSpread1DragFillBlockCompleted(ByVal sender As Object, ByVal e As FarPoint.Win.Spread.DragFillBlockCompletedEventArgs)
Handles FpSpread1.DragFillBlockCompleted
     FpSpread1.ActiveSheet.Columns(e.ColumnBegin).BackColor = Color.Yellow
End Sub