values not getting passed from datatable to dialog box - jsf

Question

<p:column>
<p:commandButton id="selectButton" update="#(form)" oncomplete="userDialog.show()" icon="ui-icon-search" title="View">
<f:setPropertyActionListener value="#{book}" target="#{CreateBookBean.selectedUser}" />
</p:commandButton>
</p:column>
</p:dataTable>
</p:outputPanel>
<p:dialog header="User Detail" modal="true" widgetVar="userDialog" width="200" height="175">
<h:panelGrid columns="2" cellpadding="5">
<h:outputLabel for="fname" value="First Name: " />
<h:outputText id="fname" value="#{CreateBookBean.selectedUser.fname}" />
<h:outputLabel for="lname" value="Last Name: " />
<h:outputText id="lname" value="#{CreateBookBean.selectedUser.lname}" />
<h:outputLabel for="mobileno" value="mobile no: " />
<h:outputText id="mobileno" value="#{CreateBookBean.selectedUser.mobileno}" />
</h:panelGrid>
</p:dialog>
i came across this example recently.
the datatable is properly getting updated with the values i enter. but when i want to display it in the dialog box its not displaying anything.
and i actually don understand why value="#{CreateBookBean.selectedUser.fname}" is used instead of value="#{CreateBookBean.fname}".
here is my java code
public class CreateBookBean {
private Book book = new Book();
private List<Book> books = new ArrayList<Book>();
private Book selectedUser;
public String reinit() {
book = new Book();
return null;
}
setters and getters are included here
}

Answer 1

Lets split this question in two parts.
First:
When you want to display updated values (e.g. with a h:outputText), you need to update this element. Updating this element means, it will fetch the current value of it's backing bean.
Do it like this:
<p:commandButton ... update="idToUpdate1, idToUpdate2, ..." >
In order to get the idToUpdate check Naming Container in JSF2/PrimeFaces.
If you have many components which need an update, I would recomment grouping them into one NamingContainer (e.g. p:outputPanel). So you only have to update the NamingContainer, and not every single component.
Second:
#CreateBookBean.selectUser.fname means: "Fetch the CreateBookBean, fetch it's property selectUser and fetch the property of selectUser called fname".
In this case you would have these class layouts:
public class CreateBookBean {
private Book selectedUser;
....
public Book getSelectedUser() {
return this.selectedUser;
}
}
public class Book {
private String fname;
....
public String getFname() {
this.fname;
}
}
#CreateBookBean.fname means: "Fetch the CreateBookBean, fetch it's property fname".
In this case you would have this class layout:
public class CreateBookBean {
private String fname;
....
public String getFname() {
return this.fname;
}
}
According to this code you posted, i guess that the CreateBookBean has a property called selectedUser (the code reveals it: target="#{CreateBookBean.selectedUser}"), and the selectUser has a property fname.

Answer 2

Use the Update attribute in the button your using to display the dialog box, for example, <p:commandButton update="dialogBoxId" . . ./> in order to display the items from your datatable.