Extjs combo提交取value值

{
       xtype:'combo',
       fieldLabel: '题目类型',
       name: 'tType',
       anchor:'95%',
          editable:false,
          mode:'local',
          triggerAction:'all',
          store:new Ext.data.ArrayStore({
             fields:['text','value'],
             data:[['单选题','Single'],
                  ['多选题','Multiple'],
                  ['填充题','FillBlank'],
                  ['简答题','Simple'],
                  ['综合题','Discuss']
                  ]
          }),
          emptyText:'请选择',
          displayField:'text',
          valueField:'value'
    }
取到的知道是text的值
要加上       hiddenName:'value',(value)是字段名 才能去到value的值