How to share Visualforce page (<apex:page/>) controller with multiple child components (<c:componentName/>)

Question

I have a Visualforce page that is essentially a form with 8 steps. It uses a custom controller. I have recently moved each step into it's own component (8 in total). Now what I am wondering is, can I use the visualforce page controller without having to call the controller again within each one of my components. When I call the controller in each component I receive the error: 'System.LimitException: Too many SOQL queries: 101'. when I omit the controller all together I also receive an error. The SOQL error was not present before I moved each step into it's own component.

Answer 1

I typically do this with the page controller directly:

<apex:page controller="XYZ">
  <c:comp1 controller="{!self}" />
  <c:comp2 controller="{!self}" />
</apex:page>

---

public class XYZ {
  public XYZ getSelf() {
    return this;
  }
}

---

<apex:component controller="ABC">
  <apex:attribute assignTo="{!pageController}" name="controller" type="XYZ" required="true" />
  ...
</apex:component>

---

public class ABC {
  public XYZ pageController { get; set; }
  ...
}

---

This design can allow you to share data between all the components, typical if you're building a multi-page wizard, for example.