I`v developed custom webpart. I can add it to page and site owners can view page with no problems.
However Site visitors/users get redirected to access denied error page. Sure, I must be doing some stuff normal users are not allowed to.
But the thing that bugs me is that when I place breakpoint in webpart constructor or even variable declaration it won't get hit! (If i try to view page with limited privileges). But in my browser, I get the access denied page. However, if I close that webpart, I instantly have access to that page and everything is OK.
What's the catch here? I was hoping I could catch exception with debugger to see which statement is guilty one, but it seems webpart doesn't execute any code and I get that exception.
Edit: Sorry, turns out debugger now hits those breakpoints. Don't know what changed, because symbols were loaded.
Found the solution.
Turns out that i wanned to determine if user belongs to a specific group by trying to access that group users. As this was impossible if a user doesn't have such a permissions, it was throwing some kind of internal exception with message
"Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack."
Anyways, i now learned to loop through SPUser.Groups (SPGroupCollection) and check if we have a matching group rather than enumerating group principals and seeing if he's inside.