DataGridView清除显示的数据、设定右键菜单

this.dgv_PropDemo.DataSource = null

DataTable dt = this.dgv_PropDemo.DataSource as DataTable;
dt.Rows.Clear();
this.dgv_PropDemo.DataSource = dt;

//设置DataGridView的右键菜单
this.dgv_Users.ContextMenuStrip = cmsDgv;
//设置列的右键菜单
this.dgv_Users.Columns[1].ContextMenuStrip = cmsColumn;
//设置列头的右键菜单
this.dgv_Users.Columns[1].HeaderCell.ContextMenuStrip = cmsHeaderCell;
//设置行的右键菜单
this.dgv_Users.Rows[2].ContextMenuStrip = cmsRow;
//设置单元格的右键菜单
this.dgv_Users[1, 2].ContextMenuStrip = cmsCell;

private void dgv_Users_CellContextMenuStripNeeded(object sender, DataGridViewCellContextMenuStripNeededEventArgs e)
{
    DataGridView dgv = sender as DataGridView;
    if (e.RowIndex < 0)
    {
         //设置列头右键
         e.ContextMenuStrip = cmsHeaderCell;
    }
    else if (e.ColumnIndex < 0)
    { 
          //设置行头右键菜单
          e.ContextMenuStrip = cmsRow;
     }
     else if (dgv[e.ColumnIndex, e.RowIndex].Value.ToString().Equals("男"))
     {
           e.ContextMenuStrip = cmsCell;
     }
     else
     {
           e.ContextMenuStrip = cmsDgv;
     }
}