Dispatcher Class
Definition
Provides services for managing work items on a thread.
public class Dispatcher
Methods
| Name | Description |
|---|---|
| AwaitWithPriority (2 overloads) | Returns a task awaitable that would invoke continuation on specified dispatcher priority |
| BeginInvokeShutdown | Begins the process of shutting down the dispatcher. |
| CheckAccess | Checks that the current thread is the UI thread. |
| DisableProcessing | Disable the event processing of the dispatcher. |
| ExitAllFrames | Requests that all nested frames exit. |
| FromThread | No summary available. |
| HasJobsWithPriority | No summary available. |
| Invoke (8 overloads) | Executes the specified Action synchronously on the thread that the Dispatcher was created on. |
| InvokeAsync (10 overloads) | Executes the specified Action asynchronously on the thread that the Dispatcher was created on. |
| InvokeShutdown | Initiates the shutdown process of the Dispatcher synchronously. |
| MainLoop | Runs the dispatcher's main loop. |
| Post (2 overloads) | Posts an action that will be invoked on the dispatcher thread. |
| PushFrame | Push an execution frame. |
| Resume (2 overloads) | Creates an awaitable object that asynchronously resumes execution on the dispatcher. |
| RunJobs | No summary available. |
| ToTaskScheduler (2 overloads) | Gets a System.Threading.Tasks.TaskScheduler which executes tasks on this Avalonia.Threading.Dispatcher. A Avalonia.Threading.DispatcherPriority is captured from the current Avalonia.Threading.AvaloniaSynchronizationContext if one is available. Otherwise, Avalonia.Threading.DispatcherPriority.Default is used. |
| VerifyAccess | Checks that the current thread is the UI thread and throws if not. |
| Yield (2 overloads) | Creates an awaitable object that asynchronously yields control back to the current dispatcher and provides an opportunity for the dispatcher to process other events. |
AwaitWithPriority overloads
AwaitWithPriority Method
Returns a task awaitable that would invoke continuation on specified dispatcher priority
public Avalonia.Threading.DispatcherPriorityAwaitable AwaitWithPriority(System.Threading.Tasks.Task task, Avalonia.Threading.DispatcherPriority priority)
Parameters
task System.Threading.Tasks.Task
priority Avalonia.Threading.DispatcherPriority
Returns
AwaitWithPriority Method
public Avalonia.Threading.DispatcherPriorityAwaitable<T><T> AwaitWithPriority<T>(System.Threading.Tasks.Task<T> task, Avalonia.Threading.DispatcherPriority priority)
Parameters
task System.Threading.Tasks.Task<T>
priority Avalonia.Threading.DispatcherPriority
Type Parameters
T
Returns
BeginInvokeShutdown Method
Begins the process of shutting down the dispatcher.
public void BeginInvokeShutdown(Avalonia.Threading.DispatcherPriority priority)
Parameters
CheckAccess Method
Checks that the current thread is the UI thread.
public bool CheckAccess()
Returns
bool
DisableProcessing Method
Disable the event processing of the dispatcher.
public Avalonia.Threading.Dispatcher.DispatcherProcessingDisabled DisableProcessing()
Returns
Avalonia.Threading.Dispatcher.DispatcherProcessingDisabled
Remarks
This is an advanced method intended to eliminate the chance of unrelated reentrancy. The effect of disabling processing is:
- CLR locks will not pump messages internally.
- No one is allowed to push a frame.
- No message processing is permitted.
ExitAllFrames Method
Requests that all nested frames exit.
public void ExitAllFrames()
FromThread Method
public Avalonia.Threading.Dispatcher FromThread(System.Threading.Thread thread)
Parameters
thread System.Threading.Thread
Returns
HasJobsWithPriority Method
public bool HasJobsWithPriority(Avalonia.Threading.DispatcherPriority priority)
Parameters
priority Avalonia.Threading.DispatcherPriority
Returns
bool
Invoke overloads
Invoke Method
Executes the specified Action synchronously on the thread that the Dispatcher was created on.
public void Invoke(Action callback)
Parameters
callback Action
An Action delegate to invoke through the dispatcher.
Remarks
Note that the default priority is DispatcherPriority.Send.
Invoke Method
Executes the specified Action synchronously on the thread that the Dispatcher was created on.
public void Invoke(Action callback, Avalonia.Threading.DispatcherPriority priority)
Parameters
callback Action
An Action delegate to invoke through the dispatcher.
priority Avalonia.Threading.DispatcherPriority
The priority that determines in what order the specified callback is invoked relative to the other pending operations in the Dispatcher.
Invoke Method
Executes the specified Action synchronously on the thread that the Dispatcher was created on.
public void Invoke(Action callback, Avalonia.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken)
Parameters
callback Action
An Action delegate to invoke through the dispatcher.
priority Avalonia.Threading.DispatcherPriority
The priority that determines in what order the specified callback is invoked relative to the other pending operations in the Dispatcher.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the operation. If the operation has not started, it will be aborted when the cancellation token is canceled. If the operation has started, the operation can cooperate with the cancellation request.
Invoke Method
Executes the specified Action synchronously on the thread that the Dispatcher was created on.
public void Invoke(Action callback, Avalonia.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken, TimeSpan timeout)
Parameters
callback Action
An Action delegate to invoke through the dispatcher.
priority Avalonia.Threading.DispatcherPriority
The priority that determines in what order the specified callback is invoked relative to the other pending operations in the Dispatcher.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the operation. If the operation has not started, it will be aborted when the cancellation token is canceled. If the operation has started, the operation can cooperate with the cancellation request.
timeout TimeSpan
The minimum amount of time to wait for the operation to start. Once the operation has started, it will complete before this method returns.
Invoke Method
public TResult Invoke<TResult>(Func<TResult> callback)
Parameters
callback Func<TResult>
Type Parameters
TResult
Returns
TResult
Invoke Method
public TResult Invoke<TResult>(Func<TResult> callback, Avalonia.Threading.DispatcherPriority priority)
Parameters
callback Func<TResult>
priority Avalonia.Threading.DispatcherPriority
Type Parameters
TResult
Returns
TResult
Invoke Method
public TResult Invoke<TResult>(Func<TResult> callback, Avalonia.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken)
Parameters
callback Func<TResult>
priority Avalonia.Threading.DispatcherPriority
cancellationToken System.Threading.CancellationToken
Type Parameters
TResult
Returns
TResult
Invoke Method
public TResult Invoke<TResult>(Func<TResult> callback, Avalonia.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken, TimeSpan timeout)
Parameters
callback Func<TResult>
priority Avalonia.Threading.DispatcherPriority
cancellationToken System.Threading.CancellationToken
timeout TimeSpan
Type Parameters
TResult
Returns
TResult
InvokeAsync overloads
InvokeAsync Method
Executes the specified Action asynchronously on the thread that the Dispatcher was created on.
public Avalonia.Threading.DispatcherOperation InvokeAsync(Action callback)
Parameters
callback Action
An Action delegate to invoke through the dispatcher.
Returns
Avalonia.Threading.DispatcherOperation
An operation representing the queued delegate to be invoked.
Remarks
Note that the default priority is DispatcherPriority.Default.
InvokeAsync Method
Executes the specified Action asynchronously on the thread that the Dispatcher was created on.
public Avalonia.Threading.DispatcherOperation InvokeAsync(Action callback, Avalonia.Threading.DispatcherPriority priority)
Parameters
callback Action
An Action delegate to invoke through the dispatcher.
priority Avalonia.Threading.DispatcherPriority
The priority that determines in what order the specified callback is invoked relative to the other pending operations in the Dispatcher.
Returns
Avalonia.Threading.DispatcherOperation
An operation representing the queued delegate to be invoked.
InvokeAsync Method
Executes the specified Action asynchronously on the thread that the Dispatcher was created on.
public Avalonia.Threading.DispatcherOperation InvokeAsync(Action callback, Avalonia.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken)
Parameters
callback Action
An Action delegate to invoke through the dispatcher.
priority Avalonia.Threading.DispatcherPriority
The priority that determines in what order the specified callback is invoked relative to the other pending operations in the Dispatcher.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the operation. If the operation has not started, it will be aborted when the cancellation token is canceled. If the operation has started, the operation can cooperate with the cancellation request.
Returns
Avalonia.Threading.DispatcherOperation
An operation representing the queued delegate to be invoked.
InvokeAsync Method
public System.Threading.Tasks.Task InvokeAsync(Func<System.Threading.Tasks.Task> callback)
Parameters
callback Func<System.Threading.Tasks.Task>
Returns
System.Threading.Tasks.Task
InvokeAsync Method
public System.Threading.Tasks.Task InvokeAsync(Func<System.Threading.Tasks.Task> callback, Avalonia.Threading.DispatcherPriority priority)
Parameters
callback Func<System.Threading.Tasks.Task>
priority Avalonia.Threading.DispatcherPriority
Returns
System.Threading.Tasks.Task
InvokeAsync Method
public System.Threading.Tasks.Task<TResult> InvokeAsync<TResult>(Func<System.Threading.Tasks.Task<TResult>> action)
Parameters
action Func<System.Threading.Tasks.Task<TResult>>
Type Parameters
TResult
Returns
System.Threading.Tasks.Task<TResult>
InvokeAsync Method
public System.Threading.Tasks.Task<TResult> InvokeAsync<TResult>(Func<System.Threading.Tasks.Task<TResult>> action, Avalonia.Threading.DispatcherPriority priority)
Parameters
action Func<System.Threading.Tasks.Task<TResult>>
priority Avalonia.Threading.DispatcherPriority
Type Parameters
TResult
Returns
System.Threading.Tasks.Task<TResult>
InvokeAsync Method
public Avalonia.Threading.DispatcherOperation<T><TResult> InvokeAsync<TResult>(Func<TResult> callback)
Parameters
callback Func<TResult>
Type Parameters
TResult
Returns
Avalonia.Threading.DispatcherOperation<T><TResult>
InvokeAsync Method
public Avalonia.Threading.DispatcherOperation<T><TResult> InvokeAsync<TResult>(Func<TResult> callback, Avalonia.Threading.DispatcherPriority priority)
Parameters
callback Func<TResult>
priority Avalonia.Threading.DispatcherPriority
Type Parameters
TResult
Returns
Avalonia.Threading.DispatcherOperation<T><TResult>
InvokeAsync Method
public Avalonia.Threading.DispatcherOperation<T><TResult> InvokeAsync<TResult>(Func<TResult> callback, Avalonia.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken)
Parameters
callback Func<TResult>
priority Avalonia.Threading.DispatcherPriority
cancellationToken System.Threading.CancellationToken
Type Parameters
TResult
Returns
Avalonia.Threading.DispatcherOperation<T><TResult>
InvokeShutdown Method
Initiates the shutdown process of the Dispatcher synchronously.
public void InvokeShutdown()
MainLoop Method
Runs the dispatcher's main loop.
public void MainLoop(System.Threading.CancellationToken cancellationToken)
Parameters
cancellationToken System.Threading.CancellationToken
A cancellation token used to exit the main loop.
Post overloads
Post Method
Posts an action that will be invoked on the dispatcher thread.
public void Post(Action action, Avalonia.Threading.DispatcherPriority priority)
Parameters
action Action
The method.
priority Avalonia.Threading.DispatcherPriority
The priority with which to invoke the method.
Post Method
Posts an action that will be invoked on the dispatcher thread.
public void Post(System.Threading.SendOrPostCallback action, object arg, Avalonia.Threading.DispatcherPriority priority)
Parameters
action System.Threading.SendOrPostCallback
The method.
arg object
The argument of method to call.
priority Avalonia.Threading.DispatcherPriority
The priority with which to invoke the method.
PushFrame Method
Push an execution frame.
public void PushFrame(Avalonia.Threading.DispatcherFrame frame)
Parameters
frame Avalonia.Threading.DispatcherFrame
The frame for the dispatcher to process.
Resume overloads
Resume Method
Creates an awaitable object that asynchronously resumes execution on the dispatcher.
public Avalonia.Threading.DispatcherPriorityAwaitable Resume()
Returns
Avalonia.Threading.DispatcherPriorityAwaitable
An awaitable object that asynchronously resumes execution on the dispatcher.
Remarks
This method is equivalent to calling the Avalonia.Threading.Dispatcher.Resume(Avalonia.Threading.DispatcherPriority) method and passing in Avalonia.Threading.DispatcherPriority.Background.
Resume Method
`` Creates an awaitable object that asynchronously resumes execution on the dispatcher. The work that occurs when control returns to the code awaiting the result of this method is scheduled with the specified priority.
public Avalonia.Threading.DispatcherPriorityAwaitable Resume(Avalonia.Threading.DispatcherPriority priority)
Parameters
priority Avalonia.Threading.DispatcherPriority
The priority at which to schedule the continuation.
Returns
Avalonia.Threading.DispatcherPriorityAwaitable
An awaitable object that asynchronously resumes execution on the dispatcher.
RunJobs Method
public void RunJobs(Nullable<Avalonia.Threading.DispatcherPriority> priority)
Parameters
priority Nullable<Avalonia.Threading.DispatcherPriority>
ToTaskScheduler overloads
ToTaskScheduler Method
Gets a System.Threading.Tasks.TaskScheduler which executes tasks on this Avalonia.Threading.Dispatcher. A Avalonia.Threading.DispatcherPriority is captured from the current Avalonia.Threading.AvaloniaSynchronizationContext if one is available. Otherwise, Avalonia.Threading.DispatcherPriority.Default is used.
public System.Threading.Tasks.TaskScheduler ToTaskScheduler()
Returns
System.Threading.Tasks.TaskScheduler
ToTaskScheduler Method
Gets a System.Threading.Tasks.TaskScheduler which executes tasks on this Avalonia.Threading.Dispatcher with the specified Avalonia.Threading.DispatcherPriority.
public System.Threading.Tasks.TaskScheduler ToTaskScheduler(Avalonia.Threading.DispatcherPriority priority)
Parameters
priority Avalonia.Threading.DispatcherPriority
Returns
System.Threading.Tasks.TaskScheduler
VerifyAccess Method
Checks that the current thread is the UI thread and throws if not.
public void VerifyAccess()
Exceptions
Yield overloads
Yield Method
Creates an awaitable object that asynchronously yields control back to the current dispatcher and provides an opportunity for the dispatcher to process other events.
public Avalonia.Threading.DispatcherPriorityAwaitable Yield()
Returns
Avalonia.Threading.DispatcherPriorityAwaitable
An awaitable object that asynchronously yields control back to the current dispatcher and provides an opportunity for the dispatcher to process other events.
Remarks
This method is equivalent to calling the Avalonia.Threading.Dispatcher.Yield(Avalonia.Threading.DispatcherPriority) method and passing in Avalonia.Threading.DispatcherPriority.Background.
Exceptions
Yield Method
Creates an cawaitable object that asynchronously yields control back to the current dispatcher and provides an opportunity for the dispatcher to process other events. The work that occurs when control returns to the code awaiting the result of this method is scheduled with the specified priority.
public Avalonia.Threading.DispatcherPriorityAwaitable Yield(Avalonia.Threading.DispatcherPriority priority)
Parameters
priority Avalonia.Threading.DispatcherPriority
The priority at which to schedule the continuation.
Returns
Avalonia.Threading.DispatcherPriorityAwaitable
An awaitable object that asynchronously yields control back to the current dispatcher and provides an opportunity for the dispatcher to process other events.
Exceptions
Properties
| Name | Description |
|---|---|
| CurrentDispatcher | No summary available. |
| SupportsRunLoops | No summary available. |
| Thread | No summary available. |
| UIThread | Gets the dispatcher for the UI thread. |
CurrentDispatcher Property
public Avalonia.Threading.Dispatcher CurrentDispatcher { get; set; }
SupportsRunLoops Property
public bool SupportsRunLoops { get; set; }
Thread Property
public System.Threading.Thread Thread { get; set; }
UIThread Property
Gets the dispatcher for the UI thread.
public Avalonia.Threading.Dispatcher UIThread { get; set; }
Remarks
Control and libraries author are encouraged to use Avalonia.Threading.Dispatcher.CurrentDispatcher and Avalonia.AvaloniaObject.Dispatcher instead.
Events
| Name | Description |
|---|---|
| ShutdownFinished | Raised when the dispatcher is shut down. |
| ShutdownStarted | Raised when the dispatcher is shutting down. |
| UnhandledException | Occurs when a thread exception is thrown and uncaught during execution of a delegate by way of Avalonia.Threading.Dispatcher.Invoke(Action) or Avalonia.Threading.Dispatcher.InvokeAsync(Action). |
| UnhandledExceptionFilter | Occurs when a thread exception is thrown and uncaught during execution of a delegate by way of Avalonia.Threading.Dispatcher.Invoke(Action) or Avalonia.Threading.Dispatcher.InvokeAsync(Action) when in the filter stage. |
ShutdownFinished Event
Raised when the dispatcher is shut down.
public event EventHandler ShutdownFinished
ShutdownStarted Event
Raised when the dispatcher is shutting down.
public event EventHandler ShutdownStarted
UnhandledException Event
Occurs when a thread exception is thrown and uncaught during execution of a delegate by way of Avalonia.Threading.Dispatcher.Invoke(Action) or Avalonia.Threading.Dispatcher.InvokeAsync(Action).
public event Avalonia.Threading.DispatcherUnhandledExceptionEventHandler UnhandledException
Remarks
This event is raised when an exception that was thrown during execution of a delegate by way of Avalonia.Threading.Dispatcher.Invoke(Action) or Avalonia.Threading.Dispatcher.InvokeAsync(Action) is uncaught. A handler can mark the exception as handled, which will prevent the internal exception handler from being called. Event handlers for this event must be written with care to avoid creating secondary exceptions and to catch any that occur. It is recommended to avoid allocating memory or doing any resource intensive operations in the handler.
UnhandledExceptionFilter Event
Occurs when a thread exception is thrown and uncaught during execution of a delegate by way of Avalonia.Threading.Dispatcher.Invoke(Action) or Avalonia.Threading.Dispatcher.InvokeAsync(Action) when in the filter stage.
public event Avalonia.Threading.DispatcherUnhandledExceptionFilterEventHandler UnhandledExceptionFilter
Remarks
This event is raised during the filter stage for an exception that is raised during execution of a delegate by way of Avalonia.Threading.Dispatcher.Invoke(Action) or Avalonia.Threading.Dispatcher.InvokeAsync(Action) and is uncaught. The call stack is not unwound at this point (first-chance exception). Event handlers for this event must be written with care to avoid creating secondary exceptions and to catch any that occur. It is recommended to avoid allocating memory or doing any resource intensive operations in the handler. The Avalonia.Threading.Dispatcher.UnhandledExceptionFilter event provides a means to not raise the Avalonia.Threading.Dispatcher.UnhandledException event. The Avalonia.Threading.Dispatcher.UnhandledExceptionFilter event is raised first, and If Avalonia.Threading.DispatcherUnhandledExceptionFilterEventArgs.RequestCatch is set to false, the Avalonia.Threading.Dispatcher.UnhandledException event will not be raised.