Member Avatar for Martje

Hey,
i have a CLR proyect where i have 2 forms, i am trying to acces the form1 class via form2.

what i did is that i included the header.h of the form in form.h but it failed so i went back and icluded thesame folder both of them are there and then it compiled fine.
then i tried to acces form1.h but it doesnt locate anything in the header so then i made a function in form1.h and not even that it wont located it wont locate.

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  • Latest Post Latest Post by jonsca

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As described, this is usually a symbol-resolution or project-configuration problem rather than a mysterious Visual Studio bug. The most common root causes are: the form class lives in a different namespace or file than you expect; the class is not declared as a managed ref type; the header in your project is not the one the compiler is seeing; or you have a circular-include problem. Below are practical checks and patterns that solve 9 times out of 10.

Checklist to diagnose

  • Make sure the project is compiled as C++/CLI (CLR enabled).
  • Verify the form declaration is a managed type (for example public ref class Form1) and that you reference the correct namespace or fully qualify the type.
  • Confirm the exact header file is part of the project and the include path is correct (watch for duplicate filenames in different folders).
  • Pay attention to case sensitivity: Form1 is not form1.
  • If you get precompiled-header errors, ensure stdafx.h (or your PCH) is included first in each .cpp.

Avoid circular includes (recommended pattern)
Forward-declare the other managed form in the consumer header, e.g. ref class Form1;, store a handle like Form1^ owner; in Form2 and include Form1.h only in Form2.cpp. Keep the public surface on Form1 minimal (public methods/properties for what Form2 needs) so headers remain lightweight.

Alternatives and quick tips
You can also use the form Owner property, Application::OpenForms, or a small public API on Form1 instead of tight coupling. When asking for help (as requested), paste the exact compiler error and the declarations (headers) involved — the error text pinpoints whether it is a missing include, wrong namespace, or a managed/native type mismatch. As noted, handling circular references carefully is key.

Recommended Answers

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Member Avatar for SgtMe

Please post your code. Don't forget to push the code button before you paste each file.

Member Avatar for jonsca

Modify the constructor of form2 to take a form1 object. Assign that to a private form object in your form2. Operate on it like you would any other object.

Member Avatar for jonsca

Caveat: I've been trying to get a sample together and have been having some problems with circular references. It's fairly trivial in C# since there are no headers.

Take a look at http://social.msdn.microsoft.com/Forums/en-US/vcgeneral/thread/097d7025-7c67-444d-909a-a91d05eb298d/ which is one of the clearest explanations I've seen as to how to do this. Also note they give some alternatives too!

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