Primefaces如何在数据表选择事件后触发另一个事件

Question

I have a datatable with selection and a commandbutton. Problem is If user doesn't select any item from datatable and clicks to button, selectedItem object returns null. I think datatable's selection event runs after my commandbutton's action method.

What i want to do is; If user Doesn't select any item from datatable and clicks the button, I will create a new SelectedItem object. But after button's action method runs, datatable changes it to null.

<p:panel id="panel1">
<p:dataTable selection="#{myController.selectedItem}"
             selectionMode="single"....
//some other stuff
</p:panel>

<p:panel id="panel2">
//some other stuff
<p:commandButton value="Create" action="myController.create"....
</p:panel>

My Controller;

SelectedItem selectedItem = new SelectedItem();

public void create(){
 selectedItem = new SelectedItem();
}

Answer 1

You can try this:
.xhtml

<p:dataTable var="result" selection="#{myController.selectedItem}"
         selectionMode="single"....

<p:commandButton actionListener="#{myController.create()}">
    <f:setPropertyActionListener value="#{result}" target="#{myController.selectedItem}" />  
</p:commandButton>      

.java

SelectedItem selectedItem = new SelectedItem();  

public void create(){
  selectedItem = new SelectedItem();
}