Hi Riva,
Sorry for the late reply! We have tested implementing your sample and it works for us!
However I would have loved if it is achieved with autocomplete keeping in mind about the look and feel and usability.
One more thing we observed is that when we want to filter data with where condition on multiple columns the results are not updated on the combo box list until we move the mouse or click somewhere! But the same is working well if the searched text is binded to "displayKey" of the combo.
Other than the above said things I find your inputs helpful for the moment!
Thanks!