MissingMethodException thrown when calling new form in Compact Framework

Question

I'm updating an old mobile device application for better flexibility. I had basically added the ability to configure the address of our SQL server in the case that we want to use our test server as opposed to our production server. I don't think this is causing the problem, but I wanted to state it. I also upgraded the project from a VS 2003 project to a VS 2005 project.

The issue I am having is that when I try to run the program in the VS emulator for Pocket PC, I get an error. It occurs after our "main menu" form loads and the user selects the next form to load. The form is initialized without issue, but when we try to run the .ShowDialog() method, it throws a System.MissingMethodException.

I don't have a lot of experience with the Compact Framework and really have no idea where to start looking for problems. I stepped the debugger through the entire initializing process for the new form and it ran without issue. But, again, when we come to the ShowDialog call, it throws the error.

Any ideas in where to start looking or known issues would be greatly appreciated.

Answer 1

I'm usually getting MissingMethodException for this reason:

• I've got at least two files in my project, for instance an .exe file and a .dll file
• I make changes to the .dll file's source code, and recompile
• VS says it deploys the new .dll file to the device, but indeed it does not (it keeps the old file)
• The .exe starts up fine, but when it starts accessing the .dll file the application throws a MissingMethodException, because it can't find the methods in the old dll file.

Fix: Delete the entire application directory from the device and redeploy.

Answer 2

I should have added this long ago. The answer ended up being that the incorrect version of .NET was installed on the Mobile Device.

Answer 3

A possible issue that can cause this situation is that the DLL is not being updated when deployed. It can be caused by the DLL in question being a dependency for more than one executable.

For example let's say executable A is running on the device and it is dependent on the DLL's method callA. You are trying to debug executable B which is also dependent on the DLL but on the method callB that you just added. When Visual Studio goes to deploy the DLL with callB in it, it is unable to do so because executable A is still using it. Visual Studio does not tell you that it was not successful in deploying the DLL. (Liar VS! ;)

To fix it, kill all the executables that depend on the DLL and then deploy it.

@Felix Alcala - You got an up vote from me. I would add this as a comment to your fix because it is directly related. Alas, I did not have the rep to do so. But, I want this answer to be public because I found it helpful

Answer 4

Start looking in the ShowDialog method itself. The error is slightly misleading - it's not ShowDialog which it can't find, but the JIT compiler is probably trying to compile ShowDialog, and throwing that exception (because ShowDialog is trying to call something it can't find). If ShowDialog is in a different assembly, then there may be something static that can't be initialized, which could similarly cause this - but start out looking in ShowDialog itself.

Because of this, one trick to finding the problem (if it isn't obvisou) is to reduce the code in ShowDialog until you find the line causing the problem. I'd start out commenting ALL the code, to confirm my hypothesis. If you no longer get the exception, try uncommenting about half of the remaining code at a time, etc.

Answer 5

当您尝试从紧凑型项目中使用常规WinForm类时，可以得到此异常。