SortCompareを利用してDataGridViewをソートする方法

SortCompareを利用してDataGridViewをソートする方法
VB.NET

Private Sub dgv1_SortCompare(ByVal sender As Object, _
        ByVal e As DataGridViewSortCompareEventArgs) _
        Handles dgv1.SortCompare
    Dim strTxt1 As String
    If e.CellValue1 Is Nothing Then
        strTxt1 = ""
    Else
        strTxt1 = e.CellValue1.ToString
    End If
    Dim strTxt2 As String
    If e.CellValue2 Is Nothing Then
        strTxt2 = ""
    Else
        strTxt2 = e.CellValue2.ToString
    End If

    e.SortResult = strTxt1.Length - strTxt2.Length
    e.Handled = True
End Sub

C#

private void dgv1_SortCompare(object sender,
    DataGridViewSortCompareEventArgs e)
{
    string strTxt1 = (e.CellValue1 == null ? "" : e.CellValue1.ToString());
    string strTxt2 = (e.CellValue2 == null ? "" : e.CellValue2.ToString());

    e.SortResult = strTxt1.Length - strTxt2.Length;
    e.Handled = true;
}