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TaskScheduler.UnobservedTaskException Event

Definition

Namespace:
System.Threading.Tasks
Assemblies:
mscorlib.dll, System.Threading.Tasks.dll
Assemblies:
netstandard.dll, System.Runtime.dll
Assembly:
System.Threading.Tasks.dll
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll
Source:
TaskScheduler.cs
Source:
TaskScheduler.cs
Source:
TaskScheduler.cs
Source:
TaskScheduler.cs
Source:
TaskScheduler.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

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;
public static event EventHandler<System.Threading.Tasks.UnobservedTaskExceptionEventArgs>? UnobservedTaskException;
[add: System.Security.SecurityCritical]
[remove: System.Security.SecurityCritical]
public static event EventHandler<System.Threading.Tasks.UnobservedTaskExceptionEventArgs> UnobservedTaskException;
member this.UnobservedTaskException : EventHandler<System.Threading.Tasks.UnobservedTaskExceptionEventArgs> 
[<add: System.Security.SecurityCritical>]
[<remove: System.Security.SecurityCritical>]
member this.UnobservedTaskException : EventHandler<System.Threading.Tasks.UnobservedTaskExceptionEventArgs> 
Public Shared Custom Event UnobservedTaskException As EventHandler(Of UnobservedTaskExceptionEventArgs)

Event Type

Attributes

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>

Applies to

See also

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