QT:4.1.1

Hi everybody!
I am trying to call a function from my combobox but i was not able. I tryied: all signals but it not works.
It would be perfect if i click on my combobox and send a signal, or call my function...
Have somebody a idea how could i call my function by clicking my combobox for example.

My Combobox is per default empty. And my idea is that when you click the combobox a query will started and values should be added to this combobox

I tried this:
Qt Code: 
  1. connect(ui.sprache_cb, SIGNAL( activated()), this, SLOT(selectSprache()));
  2. connect(ui.sprache_cb, SIGNAL( clicked()), this, SLOT(selectSprache()));
  3. connect(ui.sprache_cb, SIGNAL( highlighted()), this, SLOT(selectSprache()));
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Have i a chance to solve it?