dataGridView右键菜单并选中该行

private void dataGridView1_CellMouseDown (object sender , DataGridViewCellMouseEventArgs e )
         {
             if (e .Button = = MouseButtons .Right )
             {
                 if (e .RowIndex > = 0 )
                 {
                     dataGridView1 .ClearSelection ( ) ;
                     dataGridView1 .Rows [e .RowIndex ] .Selected = true ;
                     dataGridView1 .CurrentCell = dataGridView1 .Rows [e .RowIndex ] .Cells [e .ColumnIndex ] ;
                     contextMenuStrip1 .Show (MousePosition .X , MousePosition .Y ) ;
                 }
             }
         }