Cross-reference: Standard exceptions and error codes

his table is intended as an aid for cross-referencing Windows Runtime app error codes to the Microsoft .NET standard exceptions that you can catch as part of your app's exception handling techniques. For more info on those techniques, see Exception handling for Windows Runtime apps in C# or Visual Basic.

Notes

In the ".NET Exception" column of the table above, if the exception name is linked, that exception is part of the classes for .NET for Windows Runtime apps. That means you could raise a new exception of that type in your own code. Or you can catch those exceptions specifically as part of your exception handling for try-catch or UnhandledException. If the exception name is not linked, that exception is not part of the classes for .NET for Windows Runtime. The exceptions that aren't part of the .NET for Windows Runtime set might be encountered in certain interop scenarios, or might come from system or Windows Runtime internals. You won't be able to write catch blocks for them using that specific exception type, because that type isn't known to the .NET libraries you're running for Windows Runtime apps. But you still might be able to read an HRESULT code, look it up from the "HRESULT(s) - raw:" column, and note that there is a .NET exception that corresponds. Or you can catch it as a general Exception. Then you can read the .NET documentation and perhaps learn more about the intention of that exception and the reasons that the originating code might have thrown that exception, even if that exception wasn't represented in the .NET for Windows Runtime types.

If no (Namespace) is listed for a .NET exception, it's from the System namespace.

The constants listed in the "HRESULT(s) - symbolic" column come from a variety of sources. Some are defined in winerror.h. Some are defined in headers that are specific to Component Object Model (COM) programming, or in headers that are part of specific subsystems of Windows. Some require HRESULT_From_Win32 macro usages with codes from even earlier sets of constants (these are the ones preceded with ERROR_). For typical Windows Runtime programming when you're using a .NET language, these headers are not something that you'd have included as part of your project. If you are getting error code info for the cases where the system can't map to a standard exception, you'll probably see it as a raw integer or hex value and won't have automatic support that aliases the numeric code to the Windows named constant values. Still, there's a history of referencing error codes by their named constants instead of raw codes, based on previous Windows error reporting systems. You may be able to use the named constants you see in the table as a way to further research the error in other documentation sources such as forums or support documents, in particular what that error meant for desktop programming, Microsoft Win32 and COM, and so on.

SystemException: In the original .NET exception hierarchy, many exceptions derived from SystemException. For example, System.ArgumentException derived from SystemException. Inheritance from SystemException indicated that an exception was defined by the .NET core. SystemException wasn't included in the set of classes for .NET for Windows Runtime. All the exceptions that would have derived from SystemException under the full framework instead derive from System.Exception.

COMException: The .NET documentation suggests that COMException would be thrown for any unrecognized HRESULT, but that's not the behavior for Windows Runtime apps. Instead, COMException is typically the standard exception used for unmapped exceptions that originate from components. Unmapped exceptions from your own app code or from the system are reported as the base Exception, with a nonstandard HResult value.

ExternalException: Not included in .NET for Windows Runtime. You won't see this in the hierarchy for exceptions that do exist (like SEHException).

Related topics

Exception handling for Windows Store apps in C# or Visual Basic

System.Exception

Exceptions (C++/CX)

Debug Windows Runtime apps in Visual Studio