Avoid Grid_NeedDataSource call if Response.Redirect is called previously

Question

I have a Telerik RadGrid within a .ascx (user control) that requires a *_NeedDataSource method to populate the grid's DataSource.

The same user control is doing some user authentication, simply checking HttpContext.Current.User.Identity.IsAuthenticated and doing a Response.Redirect(url, false) if it is false.

I'm seeing exceptions being raised on our live system due to the *_NeedDataSource method being called when the user is not logged in, this seems to be possible because I pass false as the value of the endResponse parameter to Response.Redirect (which allows all subsequent page events to execute). The original author coded it this way as I assume he was going on the guidance of the community:

1. Using endResponse in a Response.Redirect
2. https://blogs.msdn.microsoft.com/tmarq/2009/06/25/correct-use-of-system-web-httpresponse-redirect/

I've been trying to work out a way that I can reliably prevent execution of *_NeedDataSource without reverting to an endResponse value of true.

I can think of some ways which involve flag setting and checking but that seems inelegant and subsequent developers could forget to implement the same pattern. I've also tried implementing a base control type to derive from which overrides OnPreRender (or whatever), similar to the response from Alexander Manekovskiy to this question: ASP.NET Redirect and End Page but I cannot work out the method to override that will prevent execution of *_NeedDataSource.

Can anyone recommend an approach that would work in this situation and wouldn't require too much cognitive overhead?

Answer 1

In the code which calls/accesses *_NeedDataSource, check the status code of the current Response. If the status code is 302, then a Response.Redirect() has been called earlier in the request handling:

if (Response.StatusCode != 302)
{
    // do something here
}