exceptionSwallowedOnCallFromCom MDA
Note
This article is specific to .NET Framework. It doesn't apply to newer implementations of .NET, including .NET 6 and later versions.
The exceptionSwallowedOnCallFromCOM managed debugging assistant (MDA) is activated when an exception is thrown from common language runtime (CLR) code called from COM via a method that does not have an unmanaged HRESULT return type.
Symptoms
A call to a managed component from COM returns with a value of FALSE or 0. Alternatively, if the method has a void return type, there may be no indication that an exception was thrown during the execution of the method. In this case, the exception will be silently caught and execution will return to the COM caller.
Cause
An exception was thrown, but there is no valid way to report it.
Resolution
Informational only, not necessarily indicative of a bug.
Effect on the Runtime
This MDA has no effect on the CLR. It only reports data about silently caught exceptions.
Output
Informational message containing the method name, type name, and exception message.
Configuration
<mdaConfig>
<assistants>
<exceptionSwallowedOnCallFromCom />
</assistants>
</mdaConfig>
