Set combo box selected item

Take a combobox with options, and an instance name of "myComboBox"
 
 
private function findItemIndex (element:ComboBox, dataString:String):int {
	var index:int = 0;
	for (var i = 0; i < element.length; i++) {
		if (element.getItemAt(i).data.toString() == dataString) {
			index = i;
			break;
		}
		else {
		}
	}
	return index;
}
 
 
then to set the value and updated the selected item, just one line of code:
 
myComboBox.selectedIndex = this.findItemIndex(myComboBox, "stringToMatch");