We Keep Coding

Compiling a C# with x86 profile in build still receives invalid win32 app

I wrote a program in C# Windows Forms. I can build the program by using the simple build solution. In the configuration manager I have it set to x86 processor. I am using Visual Studio 2012. I am on a 64 bit machine. I can run the form on 64 bit servers. when I run the form on a 32 bit server, I receive an application error simply stating, "file.exe is not a valid win32 application"

In Visual Studio Solution Explorer, right-click on your project and select Properties. On the Build tab, make sure that Platform is set to x86.
At the beginning of your program, add code to see if it's running in a 32-bit process:
Console.WriteLine("64-bit process = {0}", Environment.Is64BitProcess);
(If you have a GUI app, display a message box with that info.)
That should say false. If it doesn't say false, then you aren't creating a 32-bit application.
If it does say false and your application won't run on your 32-bit machine, then it's likely that you're copying the wrong file. Add this line:
Console.WriteLine(System.Reflection.Assembly.GetExecutingAssembly().CodeBase);
That'll tell you where the file you're executing is located. Copy from there to your servers.
You say that you're getting a message "file.exe is not a valid win32 application". Just to be certain, the 'file.exe' that it reports is the name of your application, right, and not some other exe or dll that your application depends on?
If you're okay with this application always running as 32-bit, then leaving the platform set to x86 is fine. But you might want to set it to "Any CPU" if you want it to run as 64-bit on machines that support it.

How to compile 32-bit (my OS is 64-bit) - Error exe is not a valid Win32 application

As title suggests I am compiling C# app using VS 2012 on a 64-bit machine. I would like the program being built to run on a 32-bit machine.
Right now the only help I found online was for:
Menu>Build>Configuration>
Active Solution Platform defaulted to Any CPU, and I tried that but didn't work on 32-bit machine (unless I did something wrong)
Tried Add a new one to the Debug configuration for platform x86 with build checked
Compiled and ran the app on 32-bit machine getting error A.exe is not a valid Win32 application.
My above was similar to what was done here: Link to Stack Overflow Similar Question
UPDATE 1:
The target OS is WinXP SP3 but we dont believe it has .NET 4.5 on it. I will be testing to see if compiling earlier ver of the app in .NET 4.0 will solve the problem and fix the problem. The problem may not be what the error message is displaying.

Setting your project to target AnyCPU should allow it to run on a 32bit machine, provided you aren't using a library which loads 64bit native code. If you have any dependencies, you'll need to make sure to use AnyCPU or 32-bit versions of those dependencies, as well. Also, make sure you have the proper .NET Framework installed on the 32bit machine (.NET 4.5 by default, if you're using VS 2012 with a new project).
Note that the default in VS 2012 for new projects is AnyCPU, with the Prefer 32 Bit option checked. This will cause it to always run as a 32bit application, even on your 64bit OS.
Note that, since your friend is running XP sp3, you can't use .NET 4.5. .NET 4.5 is not supported on Windows XP. You will need to change your application to target .NET 4.0, which will then work on the XP machine (if he installs the 4.0 framework).

That error is the Win32 error ERROR_BAD_EXE_FORMAT. It's generated by the loader and is what happens when you try to run a 64 bit process on a 32 bit operating system. There are other ways to see that error, but this is by far the most common reason for it to occur on a .exe file.
To compile a 32 bit process you need to target x86 in your project configuration. Another alternative would be to target AnyCPU. That will result in a 32 bit process when executed on a 32 bit OS, and a 64 bit process when executed on a 64 bit OS. It would appear that your build targets x64.

The Platform name (shown on the top of the properties, page "Build") is only a name. The same for "Active Solution Platform" in configuration editor. This is a bit confusing.
You have to make sure that the "Target platform" setting is really set to "AnyCPU" or "x86".

I had same problem. I strugle with it. and the and I found a solution.
The solution is :
Firstly choose platform target "x86". After that build your project as "release mode" not "Debug mode". finally you can run on any platform (32 bit or 64 bit).

If none of the solutions presented above helped you, then try the following:
Open the project properties and click General in the left column.
Change Platform Toolset to the one with Windows XP in it.
For example, in Visual Studio 2015 it will default be set to "Visual Studio 2015 (v140)". To be able to run on Windows XP, you have to change this to "Visual Studio 2015 - Windows XP (v140_xp)".
Now do a full rebuild, and the exe should work on Windows XP.

Winform application crashs on WINDOWS 7 -64bits

I have a huge problem on one of my winform application. Someone who use my application works on windows 7 64bits and apparently it directly crashes when the application is launching.
My application works correctly on :
-Windows XP
-Windows Vista
-Windows 7 (32bits).
I developped the application on Visual C# express 2005 (.NET 2.0).
I am wondering if there is anything I can do to recompile my application to make it work on windows 7 64bits.
I am sorry, I have no access to the computer of the person (so I can't check, exception or anything like that). I am pretty sure that this issue is known that's why I'm asking you right now.
Does anyone have an idea ?
Thank you by advance for your Help
Regards,
Joze

In project properties setting window, select tab Build and change Platform target to X86. Republish..
EDIT: to the down-voter
By doing this Windows will know your program is designed for X86 use and will install it accordingly. (I've done this with Clickonce, and it works..)

Likly you use some interop x86 DLL or COM object. Try setting for your executable Target Platform x86 (not Any CPU as it is by default).

Do you use any unmanaged (com) components in your application?
If so, most likely you're including the 32bit version. If that's the case, you will have to compile 2 different versions of your program, one including the 32bit components, and the other including the 64bit components.
If that's not the case, it means you're using some platform specific code somewhere. More details about your application could help clarify the problem.

C# 32bit project under 64bit windows

I'm working on a form application, I use plenty of hardware, Wiimote, USBjoystick and serial port. It all worked fine under 32bit windows, but I had to upgrade to 64bit for some other apps I'm working on.
I did some research and it is possible to develop x86 apps under x64 system, but now I don't know if this is what I want. The trouble maker is obviously directX sdk. AFAICS another option is, to install a virtual x86 machine specificly for developing this app (I don't want dual boot). I've never used this before, so I'm kinda worried that all this hardware won't work under virtual machine.
I'm using wiimoteLib and blueSoleil to connect bluetooth. So will this work. And do I use windows 7's virtual xp option, or a different virtual machine software? I'd probably use winXP as a virtual OS.

32 bit applications run perfectly fine on 64 bit operating systems. I have lots of my applications developed for 32 bit and they run without any issues in 64 bit. As you say you have lots of hardware used we can't be sure which may work or may not work.
best solution is to run your app in 64 bit and see if anything is not working (I am sure 95% will work) and then come back here with specific questions.

Inside IIS (7) click on Application Pools.
Find the Application Pool that is configured for your web application in the list.
Select it, then click Advanced Settings on the right.
Second setting in the list: Enable 32-Bit Applications - must be set to True.

When compiling your application in Visual Studio, try setting the target platform to x86 rather than "any CPU" (Project options/build/target platform).

I had the same problem running a 32 bit app on a 64 bit development computer. On VS 2010 I had to go to Properties/Configuration Manager/New and choose x86. Then I did a clean and rebuild and it ran fine.

C# setup with x64 target Platform does not support in windows 7 64 bit OS

I am working with c# windows form application and i am using mysql as backend. i created setup for my project by giving target platform property as x64. when i install my application in windows 7 64bit OS it installed perfectly without error. but when i open the installed application it cant open ,its shows "Windows closing the application". what is the solution for my problem. Eventhough i didnt install mysql driver.
I have another c# windows form application with DirectX without have any backend, this application also have same problem
Thanks in Advance

Here are the diagnosis steps I'd go through:
Check the event log. If the CLR has failed to load your application to start with, there may be something in there.
Try using the Fusion Log Viewer to see what's happening in terms of assembly binding.
Does the MySQL driver you're using have separate 32 and 64 bit DLLs, and are you sure you're installing the right one?
Are you able to test this without going through a full installation (i.e. build and run on a Win7 x64 box without the installer part)?
Does it still fail if you build for "Any CPU"? Or is there some specific reason why you can't do that?
Does it fail if you build for x86, which should still work fine on an x64 box? (Unless you really need to take advantage of lots of memory in your app, there can be some performance benefits to running the x86 CLR, particularly in terms of memory as every reference is half the size.)
If you create a small "test app" which doesn't use MySQL, does that fail?
Can you write a tiny console application which does use MySQL, and make that fail, thus showing a minimal amount of "user" code required to provoke the failure?

Chances are that the source of your problem is that you application is running as a 64 bit process but it has some dependency on a component that is only available in 32 bit. This is not unexpected when you depend on DirectX. MySQL I'm not so sure about.
When you build your project you decide which platform you want to target. You do that in the settings for your project in Visual Studio.
Right click on the project the in solution explorer and select Properties from the menu. It is important that you right-click on the project that creates your application and not for instance a setup project.
On the left side of the window displaying the settings you have some tabs. Select the second tab named Build.
There is list box named Platform target. This is where you determine what platform to target.
You have four choices:
Any CPU: If you choose this your application will run as the "native bitness" of your host operating system. On 64 bit Windows your application will run as 64 bit. Do not select this if you have a dependency on a component that is only available in 32 bit. If that is the case and you select this your application will run fine on 32 bit Windows but will fail on 64 bit Windows. That is the symptom you are experiencing.
x86: If you choose this your application will always run in 32 bit. Select this if you have a dependency on a component that is only available in 32 bit.
x64: If you choose this your application will always run in 64 bit and will refuse to run on 32 bit Windows. That is probably not what you intend.
Itanium: This is for another processor architecture.