title: setting value of a combobox extjs
body: <p>This is my model for my combo</p>
  
  <pre><code>Ext.define('ExtJS.myApp.ComboModel', {
      extend: 'Ext.data.Model',
      alias: 'widget.combomodel',
      fields: [
          { name: 'ID', type: 'int' },
          { name: 'title', type: 'string' }
       ]
  });
  </code></pre>
  
  <p>This is comboStore</p>
  
  <pre><code>   this.comboStore = Ext.create('Ext.data.Store', {
          model: 'ExtJS.myApp.ComboModel',
          autoLoad: true,
          scope: this,
          proxy: {
              type: 'ajax',
              scope: this,
              url: 'myApp/GetRecords',
              reader: {
                  type: 'json',
                  root: 'data'
              }
          }
      });
  
      this.myComboBox = Ext.create('Ext.form.ComboBox', {
          store: this.comboStore,
          queryMode: 'local',
          displayField: 'title',
          valueField: 'ID'
      });
  </code></pre>
  
  <p>This is the json object I get for my store:</p>
  
  <pre><code>{"ID":"111","title":"Ext Page 1"}
  </code></pre>
  
  <p>now when I try to set the value of the combobox like this.
      this.myComboBox.setValue('111');</p>
  
  <p>the combobox shows "111" instead of "Ext Page 1"</p>
  
  <p>What would I have to do so that the combobox displays displayField while setting valueField. For example. I want to set the value as "Ext Page 1" for the user to see, but When save the value, I actually want to save "111'</p>