Datagridview 上下文菜单

private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
{
    //如果点击无效区域,返回,不弹出菜单
    Point gdvPoint = this.dataGridView1.PointToScreen(new Point(0, 0));
    int totalWidth = 0;
    foreach (DataGridViewColumn col in this.dataGridView1.Columns)
    {
        totalWidth += col.Width;
    }
    if (totalWidth > this.dataGridView1.Width - this.dataGridView1.RowHeadersWidth)
    {
        totalWidth = this.dataGridView1.Width - this.dataGridView1.RowHeadersWidth;
    }
    if (MousePosition.X < gdvPoint.X + this.dataGridView1.RowHeadersWidth || MousePosition.X > (gdvPoint.X + this.dataGridView1.RowHeadersWidth + totalWidth) ||
        MousePosition.Y < gdvPoint.Y || MousePosition.Y > (gdvPoint.Y + this.dataGridView1.ColumnHeadersHeight))
    {
        e.Cancel = true;
    }
}

 Point gdvPoint = this.dataGridView1.PointToScreen(new Point(0, 0));

 int clickColumnIndex = this.dataGridView1.HitTest(MousePosition.X - gdvPoint.X, MousePosition.Y - gdvPoint.Y).ColumnIndex;