zk form reset is not working in MVVM - mvvm

Question

I am trying to use MVVM model in zk.
If i use form in zk and try to reset the value it is not binding
<?page title="" contentType="text/html;charset=UTF-8"?>
<zk>
<window border="none" apply="org.zkoss.bind.BindComposer"
viewModel="#id('ix') #init('com.Controller')"
form="#id('fx') #load(ix) #save(ix,before='add')" >
<textbox value="#bind(fx.title)"/>
<button onClick="#command('reverse', fx=fx, field='title')" label="Reverse"/>
</window>
</zk>
#Command
#NotifyChange("title")
public void reverse() {
String value = (String) fx.getField(fieldName);
String newValue = new StringBuilder(value).reverse().toString();
setTitle(newValue);
}
But if i use <textbox value="#bind(ix.title)"/> directly without form it works.
May i know whats wrong with this code.

Answer 1

I'll explain you what's wrong.
<button onClick="#command('reverse', fx=fx, field='title')" label="Reverse"/>
Here you will call the command reverse and you give 2 params with it, fx and field.
#Command
#NotifyChange("title")
public void reverse() {
Here you have your command method but you don't have parameters that you expect.
Its also not needed give the params with it cause Title is propably a global private String.
If you want to give params then this should be the code :
#Command
#NotifyChange("title")
public void reverse(#BindingParam("fx") Form fx, #BindingParam("title") String title) {
second :
form="#id('fx') #load(ix) #save(ix,before='add')" >
Not needed, you use mvvm so you call the vm by ix, this become for you absolete.
The thing what you do here is sometimes needed for grids or lists that the don't update directly by #bind but only by pushing the save button.
This is because #save is so powerfull that it will change the values in the DB without you calling a save method.
#bind(ix.title) is actually the same as #load(ix.title) #save(ix.title) but grouped in one word for sparing code.
Hopes this helps you.