If we observe a property of SWT controls, and bind it to another observable value, you must take care of those method calls which will change the property indirectly.for example, we have a Combo whose "text" property is bound to a bean's "name" property like this:
IObservableValue nameObservable = BeansObservables.observeDetailValue(obserabedDriverProfile, "name", String.class);
ISWTObservableValue nameComboObservable = SWTObservables.observeText(driverClassCombo);
bindingContext.bindValue(nameComboObservable , nameObservable, new UpdateValueStrategy(UpdateValueStrategy.POLICY_UPDATE), null);
The variable "
obserabedDriverProfile" is a observed selection in a ListViewer, it's in a master-detail scenario. If we add some code like this:
obserabedDriverProfile.addValueChangeListener(new IValueChangeListener(){
@Override
public void handleValueChange(ValueChangeEvent event) {
DriverProfile dp = (DriverProfile)event.diff.getNewValue();
driverClassCombo.removeAll();
driverClassCombo.add(dp.getName();
driverClassCombo.setText(driverClassCombo.getItem(0));
}
});
every time you change the selection in the ListViewer, the selected bean's "name" property will be set to a empty string. Why? The
removeAll method of Combo will clear it's text, and combo's "text" property is bound to selected bean's "name" property. So, the right way is:
obserabedDriverProfile.addValueChangeListener(new IValueChangeListener(){
@Override
public void handleValueChange(ValueChangeEvent event) {
DriverProfile dp = (DriverProfile)event.diff.getNewValue();
String name = dp.getName;
driverClassCombo.removeAll();
driverClassCombo.add(name);
driverClassCombo.setText(driverClassCombo.getItem(0));
}
});
posted on 2013-04-14 15:24
West Farmer 閱讀(258)
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