System.BadImageFormatException for CustomAction in Visual Studio 2010 Setup project

Hold your guns! I did check to see if all the project outputs are set to the same processor architecture (in this case, x64). They are. So what am I trying to do?

1. Wrote a plugin for Autodesk Revit Architecture 2011 x64
   • targets .NET 3.5
   • x64
2. Created a setup project
3. Created a custom action (RegisterRevit2011Addin) for registering plugin with Revit using a supplied DLL (RevitAddInUtility.dll)
   • targets .NET 3.5
   • x64
4. added custom action to setup project, build, install

This is the error 开发者_开发百科message I get:

Error 1001. Exception occurred while initializing the installation: System.BadImageFormatException: Could not load file or assembly 'RegisterRevit2011, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. An attempt was made to load a program with an incorrect format.

Just to be sure, I created a simple console test application:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var register = new RegisterRevit2011Addin.RegisterAddinCustomAction();
            Console.WriteLine(register);
            register.Context = new System.Configuration.Install.InstallContext();
            register.Context.Parameters.Add("assemblypath",     typeof(Program).Assembly.Location);
            register.Install(new Dictionary<string, string>());
            Console.ReadLine();
        }
    }
}

I compiled this targeting x64 and .NET 3.5 - voilà, it works! So I can now assume the error lies somewhere in the setup project. I have set the target platform in the setup projects properties and also set the Launch condition to 3.5.

Interesting: When I check the resulting setup.exe with dumpbin /headers, it informs me that its a x86 process!

I'm pretty sure this all worked the day before yesterday, so I'm kinda worried I messed up my system somehow. Any ideas?

This sounds like it could be the answer: Link

Basically, Visual Studio (at least in the 2005 edition) runs custom actions with a 32bit shim. Manually changing that to 64bit after building the msi could do the trick. I'm looking into that right now.