I say is this:
<LayoutSettings AllowSelectColumns="Yes"  AllowContextMenu="true" >

        </LayoutSettings>

now i see the "remove this column"  enable!

But thank you  all the  same

I see how to hide column by javascript Code!

But i want to know

how to hide one column by Filter in WebGrid 7?  Please help me!

I can delete several rows  by js Code
//获取选择的N行
 function ShowSelection()
        {
      var grid = ISGetObject("WebGrid1");
      var rows = grid.RootTable.GetCheckedRows();      
      var arr=new Array();
 while(rows.length!=0)
 {
 for (var i=0;i<rows.length; i++)
                {         
                    var row = grid.RootTable.ToRowObject(rows[i]);
                    arr[i]=String(row.KeyValue);//行的主键值
                }
return arr;  break;
               
 }
 if(rows.length==0)
  {alert('至少选择两行！');
  return arr;
   }      

        }

the problem has been resolved.thank you all the same