Developer technologies | Windows Presentation Foundation
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Issue with AssemblyLoadContext Unload in .NET
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MakesYT Liao
0
Reputation points
I am using AssemblyLoadContext in a .NET WPF project (net8.0-windows10.0.19041.0), and I am encountering a strange issue. If I load the DLL in App.cs, I cannot manually unload it later. However, if I load and unload the DLL by pressing a button after the program starts, it can be unloaded correctly. The code for both cases is almost identical. During uninstallation, I also saw a different symptom through WinDbg. Any idea what could be causing this issue?
Symptom seen through WinDbg during uninstallation:
Loading the DLL manually later:
Loading the DLL in App.cs (can't unload):
Developer technologies | Windows Presentation Foundation
Developer technologies | .NET | Other
Developer technologies | .NET | Other
Microsoft Technologies based on the .NET software framework. Miscellaneous topics that do not fit into specific categories.
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MakesYT Liao 0 Reputation points
2023-12-13T03:06:37.6333333+00:00 -
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Hui Liu-MSFT 48,711 Reputation points Microsoft External Staff2023-12-14T08:06:24.3966667+00:00 Hi,@MakesYT Liao. The behavior you're describing might be related to the way assemblies are loaded and how the AssemblyLoadContext is being used. It's important to note that manually unloading assemblies can be a complex task, and it's not always straightforward due to the interdependencies and complexities of the .NET runtime.
Without the specific code, it's challenging to pinpoint the exact issue, but I can offer some general advice and considerations:
AssemblyLoadContext.Unload Method:
Ensure that you are using the Unload method of the AssemblyLoadContext correctly. This method unloads the assemblies loaded in that specific context. Make sure that you're not referencing any types or instances from the unloaded assembly after calling Unload.
Dependency Chains:
If your DLL has dependencies on other assemblies, make sure you unload them in the correct order. Unloading an assembly that other assemblies depend on can lead to unexpected behavior.
Static Resources:
Be cautious of static resources or static variables in your loaded assemblies. If there are static resources holding references to types from the loaded assembly, the assembly might not be eligible for garbage collection, preventing it from being unloaded.
AppDomain:
Keep in mind that AssemblyLoadContext is not the same as AppDomain unloading. If you are dealing with legacy assemblies or have complex dependencies, you might consider using separate AppDomains for isolation and unloading.
Could you provide a minimal complete code project (including assembly loading and unloading related parts) that can reproduce the problem? And share the complete troubleshooting details of wdbg.
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