DataGridView sorting with nulls in DateTime column

Question

I\'ve got a DataGridView control in a Windows forms application. There are four columns with string data and three with DateTime data. I\'m adding the rows programmatically

Answer 1

Here's the solution I came up with. The DataGridView raises a SortCompare event that you can use to input custom sorting. I'm handling that event and making null values sort out higher than non-null values (you could just as easily make nulls lower than non-nulls). Here's the VB code. I'm assuming every cell value is IComparable (if not it will be handled by the normal error handling logic.)

Try
    If e.CellValue1 Is Nothing OrElse e.CellValue1.Equals(DBNull.Value) Then
        If e.CellValue2 Is Nothing OrElse e.CellValue2.Equals(DBNull.Value) Then
            e.SortResult = 0
        Else
            e.SortResult = 1
        End If
    Else
        If e.CellValue2 Is Nothing OrElse e.CellValue2.Equals(DBNull.Value) Then
            e.SortResult = -1
        Else
            e.SortResult = DirectCast(e.CellValue1, IComparable).CompareTo(DirectCast(e.CellValue2, IComparable))
        End If
    End If
    e.Handled = True
Catch ex As Exception
    HandleError("Error sorting result grid values", ex)
    Close()
End Try

If anybody has any improvements on this please feel free to post them.