title: combobox with big store. how to set value
body: <p>I have a combobox, which has these properties:</p>
  
  <pre><code>displayField:'name',
  valueField:'id'
  </code></pre>
  
  <p>Its store may contain thousands or millions of rows. When a user pushes one button, the server returns the json for the form which looks like this:</p>
  
  <pre><code>{"field_one":"abrakadabra","combobox_with_large_store":"123"}
  </code></pre>
  
  <p>Here <code>123</code> is an <code>id</code> of a particular row. I then need to show a "user-friendly" value (displayField), but to do this I should first load this value to the store. But I'm not sure, what it the best way to do this - should I track <code>change</code> event or something else. The problem with <code>change</code> event is that a user may print some values in the combo to query its store and among those values may be numeric ones (so it is impossible to differentiate between numeric id which is a true value and some numeric values printed by the user). So, what I need is an advise on how to set and load value of the combobox with large store (having in mind that the user may query this store with numeric values). </p>