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PODifferentiating between events raised by user interaction and my own code
 

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    <p>The <code>SelectedIndexChanged</code> event gets fired in my application from a combo box when:</p> <ol> <li>the user chooses a different item in the combo box, or when:</li> <li>my own code updates the combo box's <code>SelectedItem</code> to reflect that the combo box is now displaying properties for a different object.</li> </ol> <p>I am interested in the <code>SelectedIndexChanged</code> event for case 1, so that I can update the current object's properties. But in case 2, I do not want the event to fire, because the object's properties have not changed.</p> <p>An example may help. Let's consider that I have a list box containing a list of people and I have a combo box representing the nationality of the currently selected person in the list. Case 1 could happen if Fred is currently selected in the list, and I use the combo box to change his nationality from English to Welsh. Case 2 could happen if I then select Bob, who is Scottish, in the list. Here, my list update event-handler code sees that Bob is now selected, and updates the combo box so that Scottish is now the selected item. This causes the combo box's <code>SelectedIndexChanged</code> event to be fired to set Bob's nationality to Scottish, even though it already is Scottish.</p> <p><strong>How can I update my combo box's <code>SelectedItem</code> property without causing the <code>SelectedIndexChanged</code> event to fire?</strong> One way would be to unregister the event handler, set <code>SelectedItem</code>, then re-register the event handler, but this seems tedious and error prone. There must be a better way.</p>
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