Using <Apex:Component> to add a Visualforce page within a Visualforce page and Viewstate

Question

To avoid an object from getting too big I'm building seperate objects with their own Visualforce component pages. The main Visualforce page uses tabs where I am calling each componenet page.

By doing this will the viewstate on the main page be kept under the limit ? Or do called component Visualforce pages add to the main page view state ?

Also, how can I relate all of the Visualforce components to the main Visualforce page for reporting ?

Unfortunately I'm dealing with many fields and don't want to run into view state errors forcing me to write more HTML along with any transient property definitions in the controller (which is very light.)

Answer 1

The answer is anything on the VF page, counts towards view state.

And that you got all other details as provided by sfdcfox, you can actually do a very quick test to check how your view state is impacted with or without using <apex:component>.

You can do a very quick check using an example and see how the view state changes.

As an example, using the below component and vf page code, you can see the difference how the view state is impacted. This kind of will give you an idea that anything on the page is going to impact your view state.

Component

<apex:component >
    <h1>Congratulations</h1>
    This is your new Component: mynewcomponent
</apex:component>

VF Page without component

<apex:page controller="ContactEditController">
    <apex:form >
        This is my VF Page<br/>
    </apex:form>
</apex:page>

View State in this case is as:

VF Page with component

<apex:page controller="ContactEditController">
    <apex:form >
        This is my VF Page<br/>
    </apex:form>
    <c:myVFComponent />
</apex:page>

View State in this case increases:

Answer 2

By doing this will the viewstate on the main page be kept under the limit ? Or do called component Visualforce pages add to the main page view state ?

Everything in the page increases the view state. Best case scenario, it will do absolutely nothing to improve this problem, and most likely it will exacerbate it.

Also, how can I relate all of the Visualforce components to the main Visualforce page for reporting ?

This happens automatically by the virtue of metadata relationships, but you can't really query on it.

Unfortunately I'm dealing with many fields and don't want to run into view state errors forcing me to write more HTML along with any transient property definitions in the controller (which is very light.)

Sorry, that's the nature of the beast. You need to figure out what you can make transient in order to minimize view state. This is a major limitation of Visualforce, and one of the main reasons why Lightning is so effective.