无法调试他人编写的C# WPF类库项目，求助解决启动报错问题

Hey there, let's work through this debugging issue together. That error message is spelling out exactly what's going on—you're trying to launch a class library project directly, and these types of projects don't have their own executable entry point. Since you mentioned the project is already running in production, here are a few practical ways to get debugging up and running:

1. Check for a hidden executable project in the solution #

First, let's rule out the possibility that a WPF app project is already in your solution but hidden:

• Open the Solution Explorer, then click the "Show All Files" button (the eye icon at the top). Sometimes projects get excluded or hidden by accident.
• If you spot a WPF Application (.exe) project that was missing, right-click it and select "Include in Project".
• Then right-click that executable project and choose "Set as Startup Project". You should now be able to debug normally.

2. Add a new WPF executable project to act as the debugger host #

If there's no existing exe project in the solution, you can create one to trigger the library's code:

• Right-click your solution in Solution Explorer → Add → New Project. Pick "WPF App" (make sure to select the same .NET framework version as your class library—mismatches will cause reference errors).
• Right-click the new WPF project → Add → Reference → Select your class library project from the "Projects" tab.
• Hook up the library's logic: If the library has a main window or startup class, instantiate it in your new project's App.xaml.cs or MainWindow.xaml.cs. For example:

  // In MainWindow.xaml.cs constructor
  var libraryMainWindow = new YourLibraryNamespace.MainWindow();
  libraryMainWindow.Show();
  

• Finally, right-click the new WPF project and set it as the Startup Project. Hit F5, and your breakpoints in the class library should trigger when the code runs.

3. Attach the debugger to an external running process #

If the class library is meant to be used by an already deployed external program, you can attach Visual Studio directly to that process:

• Launch the external program that uses your class library.
• In Visual Studio, go to the top menu: Debug → Attach to Process.
• In the process list, find the name of the external program, select it, and click "Attach".
• Set breakpoints in your class library code—when the external program calls into the library, the debugger will catch those breakpoints.

A quick heads-up: Always double-check that the .NET framework version of your startup project (or external program) matches the class library's version. Mismatches can break debugging or cause runtime errors.

内容的提问来源于stack exchange，提问作者BBoone