Setting 32-bit x86 build target in Visual C# 2008

Question

I'm building a C# application that loads a 32-bit COM dll. The compiled application runs fine on 32-bit Windows but barfs on 64 bit Windows because it can't load the 32-bit COM. Is there a way to set a 32-bit build target in VC# 2008 Express Edition?

Alternatively, is there a way to force a .NET application compiled to the AnyCPU build target to run in 32-bit mode on 64-bit Windows?

Answer 1

You cannot explicitly set it to 32-bit in the UI in VS Express, but apparently (I only have the Professional version at hand) it can be done using a bit of setting up. This forum post has details on how to do it.

What you can also do is to use the CorFlags tool that comes with the .Net Framework SDK to set the compiled output to run as 32-bit. To set the 32-bit flag using CorFlags, run this from the command line:

CorFlags.exe /32BIT+ yourapp.exe

This will set a flag in the header of your exe to signal to .Net that it should be run as 32-bit.

Answer 2

For posterity, here is the forum post adrian linked to:

In VC# Express, this property is missing, but you can still create an x86 configuration if you know where to look.

It looks like a long list of steps, but once you know where these things are it's a lot easier. Anyone who only has VC# Express will probably find this useful. Once you know about Configuration Manager, it'll be much more intuitive the next time.

1. In VC# Express 2005, go to Tools -> Options.
2. In the bottom-left corner of the Options dialog, check the box that says, "Show all settings".
3. In the tree-view on the left hand side, select "Projects and Solutions".
4. In the options on the right, check the box that says, "Show advanced build configuraions."
5. Click OK.
6. Go to Build -> Configuration Manager...
7. In the Platform column next to your project, click the combobox and select "".
8. In the "New platform" setting, choose "x86".
9. Click OK.
10. Click Close.

There, now you have an x86 configuration! Easy as pie! :-)

I also recommend using Configuration Manager to delete the Any CPU platform. You really don't want that if you ever have depedencies on 32-bit native DLLs (even indirect dependencies).