Getting hidden control of parent from iFramed code-behind

In my parent page I have a hidden control:

<input type="hi开发者_Go百科dden" id="CaseID" value="" runat="server" />

I need for my page in the iFrame to be able to get this value from C# code-behind. I have so far been unsuccessful.

In the child page's code-behind I have tried variations of this:

var theParent = this.Page.Parent;

But I always get null back.

Any assistance would be greatly appreciated.

From the server's perspective, there is no relationship at all between a page which launches an iframe, and the page which is contained within that iframe. They are two completely distinct and unrelated HTTP Requests. In your code-behind, they have nothing in common and there is no way to refer to one from the other.

Thus, you'll need to use the same approach as you would if you needed to "move" data from one page to another. Two common ways (though by no means are these the only ways or even the best ways) are:

• The Session object. PageABC can store a piece of data in the session, and PageXYZ can read that data from the session.
• URL Parameter on the request. PageABC can call a URL (maybe even use it as the SRC of an iFrame, hint-hint) something like this: PageXYZ.aspx?someKey=someValue. PageXYZ can access URL params from the Request object (Request["someKey"])

Something else to consider: if PageABC and PageXYZ operate in conjunction with each other, maybe having them be separate pages isn't the best approach. It may make more sense for PageXYZ to actually be ControlXYZ and be contained on PageABC. It can still be presented to the user as a popup using jQuery dialogs (or using UpdatePanels and ModalPopupExtenders, if you're masochistic ;).