Targeting both 32bit and 64bit with Visual Studio

Question

I have a little dilemma on how to set up my visual studio builds for multi-targeting.

Background: c# .NET v2.0 with p/invoking into 3rd party 32 bit DLL's, SQL compact v3.5 SP1, with a Setup project. Right now, the platform target is set to x86 so it can be run on Windows x64.

The 3rd party company has just released 64 bit versions of their DLL's and I want to build a dedicated 64bit program.

This raises some questions which I haven't got the answers to yet. I want to have the exact same code base. I must build with references to either the 32bit set of DLL's or 64bit DLL's. (Both 3rd party and SQL Server Compact)

Can this be solved with 2 new sets of configurations (Debug64 and Release64) ?

Must I create 2 separate setup projects(std. visual studio projects, no Wix or any other utility), or can this be solved within the same .msi?

Any ideas and/or recommendations would be welcomed.

Answer 1

Not sure of the total answer to your question - but thought I would point out a comment in the Additional Information section of the SQL Compact 3.5 SP1 download page seeing you are looking at x64 - hope it helps.

Due to changes in SQL Server Compact SP1 and additional 64-bit version support, centrally installed and mixed mode environments of 32-bit version of SQL Server Compact 3.5 and 64-bit version of SQL Server Compact 3.5 SP1 can create what appear to be intermittent problems. To minimize the potential for conflicts, and to enable platform neutral deployment of managed client applications, centrally installing the 64-bit version of SQL Server Compact 3.5 SP1 using the Windows Installer (MSI) file also requires installing the 32-bit version of SQL Server Compact 3.5 SP1 MSI file. For applications that only require native 64-bit, private deployment of the 64-bit version of SQL Server Compact 3.5 SP1 can be utilized.

I read this as "include the 32bit SQLCE files as well as the 64bit files" if distributing for 64bit clients.

Makes life interesting I guess.. must say that I love the "what appears to be intermittent problems" line... sounds a bit like "you are imagining things, but just in case, do this..."

Answer 2

One .Net build with x86/x64 Dependencies

While all other answers give you a solution to make different Builds according to the platform, I give you an option to only have the "AnyCPU" configuration and make a build that works with your x86 and x64 dlls.

You have to write some plumbing code for this. I could not get this working with app.config. If somebody else knows a way to solve it via app.config I really would like to know.

Resolution of correct x86/x64-dlls at runtime

Steps:

1. Use AnyCPU in csproj
2. Decide if you only reference the x86 or the x64 dlls in your csprojs. Adapt the UnitTests settings to the architecture settings you have chosen. It's important for debugging/running the tests inside VisualStudio.
3. On Reference-Properties set Copy Local & Specific Version to false
4. Get rid of the architecture warnings by adding this line to the first PropertyGroup in all of your csproj files where you reference x86/x64: <ResolveAssemblyWarnOrErrorOnTargetArchitectureMismatch>None</ResolveAssemblyWarnOrErrorOnTargetArchitectureMismatch>

5. Add this postbuild script to your startup project, use and modify the paths of this script sp that it copies all your x86/x64 dlls in corresponding subfolders of your build bin\x86\ bin\x64\

   xcopy /E /H /R /Y /I /D $(SolutionDir)\YourPathToX86Dlls $(TargetDir)\x86 xcopy /E /H /R /Y /I /D $(SolutionDir)\YourPathToX64Dlls $(TargetDir)\x64

   --> When you would start application now, you get an exception that the assembly could not be found.

6. Register the AssemblyResolve event right at the beginning of your application entry point

   AppDomain.CurrentDomain.AssemblyResolve += TryResolveArchitectureDependency;
   

   withthis method:

   /// <summary>
   /// Event Handler for AppDomain.CurrentDomain.AssemblyResolve
   /// </summary>
   /// <param name="sender">The app domain</param>
   /// <param name="resolveEventArgs">The resolve event args</param>
   /// <returns>The architecture dependent assembly</returns>
   public static Assembly TryResolveArchitectureDependency(object sender, ResolveEventArgs resolveEventArgs)
   {
       var dllName = resolveEventArgs.Name.Substring(0, resolveEventArgs.Name.IndexOf(","));
   
       var anyCpuAssemblyPath = $".\\{dllName}.dll";
   
       var architectureName = System.Environment.Is64BitProcess ? "x64" : "x86";
   
       var assemblyPath = $".\\{architectureName}\\{dllName}.dll";
   
       if (File.Exists(assemblyPath))
       {
           return Assembly.LoadFrom(assemblyPath);
       }
   
       return null;
   }
   

7. If you have unit tests make a TestClass with a Method that has an AssemblyInitializeAttribute and also register the above TryResolveArchitectureDependency-Handler there. (This won't be executed sometimes if you run single tests inside visual studio, the references will be resolved not from the UnitTest bin. Therefore the decision in step 2 is important.)

Benefits:

• One Installation/Build for both platforms

Drawbacks: - No errors at compile time when x86/x64 dlls do not match. - You should still run test in both modes!

Optionally create a second executable that is exclusive for x64 architecture with Corflags.exe in postbuild script

Other Variants to try out: - You would not need the AssemblyResolve event handler if you assure otherwise that the dlls get copied in your binary folder at start (Evaluate Process architecture -> move corresponding dlls from x64/x86 to bin folder and back.) - In Installer evaluate architecture and delete binaries for wrong architecture and move the right ones to the bin folder.