DataGridViewのセル背景色にグラデーションをかける方法

DataGridViewのセル背景色にグラデーションをかける方法
VB.NET

Private Sub dgv1_CellPainting(ByVal sender As Object, _
        ByVal e As DataGridViewCellPaintingEventArgs) _
        Handles dgv1.CellPainting
    If e.ColumnIndex >= 0 AndAlso e.RowIndex >= 0 AndAlso _
        (e.PaintParts And DataGridViewPaintParts.Background) = _
            DataGridViewPaintParts.Background Then

        Dim bColor1, bColor2 As Color
        If (e.PaintParts And DataGridViewPaintParts.SelectionBackground) = _
                DataGridViewPaintParts.SelectionBackground AndAlso _
            (e.State And DataGridViewElementStates.Selected) = _
                DataGridViewElementStates.Selected Then
            bColor1 = e.CellStyle.SelectionBackColor
            bColor2 = Color.Black
        Else
            bColor1 = e.CellStyle.BackColor
            bColor2 = Color.LemonChiffon
        End If

        Dim b As New System.Drawing.Drawing2D.LinearGradientBrush( _
            e.CellBounds, bColor1, bColor2, _
            System.Drawing.Drawing2D.LinearGradientMode.Horizontal)
        Try
            e.Graphics.FillRectangle(b, e.CellBounds)
        Finally
            b.Dispose()
        End Try

        Dim paintParts As DataGridViewPaintParts = _
            e.PaintParts And Not DataGridViewPaintParts.Background
        e.Paint(e.ClipBounds, paintParts)

        e.Handled = True
    End If
End Sub

C#

private void dgv1_CellPainting(object sender,
    DataGridViewCellPaintingEventArgs e)
{
    if (e.ColumnIndex >= 0 && e.RowIndex >= 0 &&
        (e.PaintParts & DataGridViewPaintParts.Background) ==
            DataGridViewPaintParts.Background)
    {
        Color bColor1, bColor2;
        if ((e.PaintParts & DataGridViewPaintParts.SelectionBackground) ==
                DataGridViewPaintParts.SelectionBackground &&
            (e.State & DataGridViewElementStates.Selected) ==
                DataGridViewElementStates.Selected)
        {
            bColor1 = e.CellStyle.SelectionBackColor;
            bColor2 = Color.Black;
        }
        else
        {
            bColor1 = e.CellStyle.BackColor;
            bColor2 = Color.LemonChiffon;
        }
        using (System.Drawing.Drawing2D.LinearGradientBrush b =
            new System.Drawing.Drawing2D.LinearGradientBrush(
            e.CellBounds, bColor1, bColor2,
            System.Drawing.Drawing2D.LinearGradientMode.Horizontal))
        {
            e.Graphics.FillRectangle(b, e.CellBounds);
        }

        DataGridViewPaintParts paintParts =
           e.PaintParts & ~DataGridViewPaintParts.Background;
        e.Paint(e.ClipBounds, paintParts);

        e.Handled = true;
    }
}