Ext 表格得到所有行，并得到相应的列值

//取出被所有列值   function getGridValue(gridname){      var grid = Ext.getCmp(gridname);            var grid_data = grid.getStore();      //var data_ids = "";       var data_values = "";      for(var i= 0 ;i< grid_data.data.length;i++){          var row = grid_data.getAt(i);          var id = row.get("class_unid");          var year = row.get("score");          if(year == "") year = "null";          data_values += ";"+id+","+year;      }      data_values = data_values.substring(1);            return data_values;   }  

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