Extjs怎么删除Grid的记录

下面代码是Ext.grid.GridPanel 的一个tbar的Ext.Button提交删除:

   1:  tbar : [new Ext.Button ({allowDepress : false,

   2:          handler : function() {NewHall();},

   3:          iconCls : 'add',

   4:          text : '新增'

   5:      })

   6:  ,            

   7:  new Ext.Button ({allowDepress : false,

   8:          handler : function() {

   9:          Ext.MessageBox.confirm('提示', '确实要删除所选的记录吗?',function (btn){

  10:          if(btn=='yes'){           

  11:          var row=extWindowDepartmentList.getSelections();           

  12:          var jsonData="";           

  13:          for(var i=0,len=row.length;i<len;i++){             

  14:          var ss = row[i].get("Id"); //这里为Grid数据源的Id列           

  15:          if(i==0)              

  16:          jsonData = jsonData + ss;                    

  17:          else              

  18:          jsonData = jsonData + ","+ ss;             }          

  19:          var conn = new Ext.data.Connection();          

  20:          conn.request(

  21:          {          url: "/Department/Del",        //提交的删除地址   

  22:          params:{strProjects:jsonData},            

  23:          method: 'post',            

  24:          scope: this,            

  25:          callback:function(options,success, response){            

  26:          if(success){                

  27:          Ext.MessageBox.alert("提示","所选记录成功删除！");

  28:          extWindowDepartmentList.store.reload({params:{start:0, limit:25}}); //重新load数据

  29:          }

  30:          else

  31:          {Ext.MessageBox.alert("提示","所选记录删除失败！");}

  32:          }

  33:          }) 

  34:          } 

  35:          })

  36:          ;},

  37:          iconCls : 'del',

  38:          text : '删除'

  39:      })

  40:  ]