var val = getComponent("combobox1").getValue();
var tview = database.getView("(searchView)")
var vdoc = tview.getDocumentByKey(val,true);
if(vdoc!=null){
getComponent("field1").setValue(vdoc.getItemValueString("TargetField"));
//set the in memory doc field, too
document1.replaceItemValue("field1",vdoc.getItemValueString("TargetField"))
}
Be sure to perform a partial update either the field itself or the panel containing it.