TaskScheduler.UnobservedTaskException Event

Definition

Namespace:

System.Threading.Tasks

Assembly:

System.Runtime.dll

Source:

TaskScheduler.cs

Occurs when a faulted task's unobserved exception is about to trigger exception escalation policy, which, by default, would terminate the process.

public:
 static event EventHandler<System::Threading::Tasks::UnobservedTaskExceptionEventArgs ^> ^ UnobservedTaskException;

public static event EventHandler<System.Threading.Tasks.UnobservedTaskExceptionEventArgs>? UnobservedTaskException;

member this.UnobservedTaskException : EventHandler<System.Threading.Tasks.UnobservedTaskExceptionEventArgs> 

Public Shared Custom Event UnobservedTaskException As EventHandler(Of UnobservedTaskExceptionEventArgs) 

Event Type

EventHandler<UnobservedTaskExceptionEventArgs>

Remarks

This event provides a mechanism to prevent exception escalation policy (which, by default, terminates the process) from triggering.

To make it easier for developers to write asynchronous code based on tasks, unobserved exceptions raise the UnobservedTaskException exception, but the process does not terminate by default. Instead, the exception is handled by the runtime after the event is raised, regardless of whether an event handler observes the exception. This behavior can be configured. You can use the <ThrowUnobservedTaskExceptions> configuration element to terminate the process instead:

<configuration>
   <runtime>
      <ThrowUnobservedTaskExceptions enabled="true"/>
   </runtime>
</configuration>

See also

• Task Parallel Library (TPL)
• <ThrowUnobservedTaskExceptions> Element