ASP.NET Server Control - Is shared Viewstate between controls possible

Question

If I have a master 'composite custom server control', with several child custom controls, is it possible, for the master control to share its viewstate with the child controls, which are also custom composite server controls,(all of the controls are composite custom server controls)?

To expand a little more, say I have a Person control, Address control, Phone control and Notes control. Address, Phone and Notes can exist as either independant controls, or as part of the Person control. Since each control is responsible for its own viewstate, and stores required data in it, so it can render/postback etc, it ends up that there is a lage duplication in the viewstate, since the Person control stores all the data, and then each child control stores its own data again. Also, to further complicate things, the Person Control adds the child controls dynamically, so its possible to add a 2nd address/phone number/note etc,which can cause yet a larger viewstate(up to 1MB).

In the case of when all the Address/Phone/etc controls are children of the the Person Control, is it possible for me to somehow share common viewstate data, so I dont have 2/3/4 copies of some stuff in the viewstate, and when they are not components, just act as normal?

I do have one idea for a solution, but its fairly nasty imo, where I could modify the Person control, expose its viewstate or the data, and then in the child control, would check the control hierarchy, and if the child control is part of a Person, dont use to its own viewstate, use the exposed one. This would require me to rework alot of the existing code, which I'd rather avoid if possible.

Answer 1

The first question I'd ask is, "How much of this data do you really need to keep on the ViewState?" For example, is there enough information in a typical page request to be able to rebuild all of the information that is in some of these controls?

I find that ASP.NET typically uses ViewState far more than I really need it to, and if you're getting a 1MB viewstate, I suspect the same is probably true for you. I highly recommend reading this article to get a more full understanding of how ViewState works, what causes values to get saved to ViewState, and how to avoid using it where it's not necessary. You may be able to solve the bulk of your problem simply by doing more of your work in Page_Init instead of Page_Load, for example.