Dispatcher.Invoke Method

Reference

Definition

Namespace:: System.Windows.Threading

Assembly:: WindowsBase.dll

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.

Executes the specified delegate synchronously on the thread the Dispatcher is associated with.

Overloads

Invoke(DispatcherPriority, TimeSpan, Delegate, Object, Object[])	Executes the specified delegate at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.
Invoke(DispatcherPriority, TimeSpan, Delegate, Object)	Executes the specified delegate at the specified priority with the specified argument synchronously on the thread the Dispatcher is associated with.
Invoke(DispatcherPriority, Delegate, Object, Object[])	Executes the specified delegate at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.
Invoke(Action, DispatcherPriority, CancellationToken, TimeSpan)	Executes the specified Action synchronously at the specified priority on the thread the Dispatcher is associated with.
Invoke(DispatcherPriority, TimeSpan, Delegate)	Executes the specified delegate synchronously at the specified priority and with the specified time-out value on the thread the Dispatcher was created.
Invoke(DispatcherPriority, Delegate, Object)	Executes the specified delegate at the specified priority with the specified argument synchronously on the thread the Dispatcher is associated with.
Invoke(Delegate, TimeSpan, DispatcherPriority, Object[])	Executes the specified delegate within the designated time span at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.
Invoke(Delegate, TimeSpan, Object[])	Executes the specified delegate within the designated time span at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.
Invoke(Action, DispatcherPriority, CancellationToken)	Executes the specified Action synchronously at the specified priority on the thread the Dispatcher is associated with.
Invoke(DispatcherPriority, Delegate)	Executes the specified delegate synchronously at the specified priority on the thread that the Dispatcher is associated with.
Invoke(Delegate, Object[])	Executes the specified delegate with the specified arguments synchronously on the thread the Dispatcher is associated with.
Invoke(Action, DispatcherPriority)	Executes the specified Action synchronously at the specified priority on the thread the Dispatcher is associated with.
Invoke(Action)	Executes the specified Action synchronously on the thread the Dispatcher is associated with.
Invoke(Delegate, DispatcherPriority, Object[])	Executes the specified delegate at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.
Invoke<TResult>(Func<TResult>)	Executes the specified Func<TResult> synchronously on the thread the Dispatcher is associated with.
Invoke<TResult>(Func<TResult>, DispatcherPriority)	Executes the specified Func<TResult> synchronously at the specified priority on the thread the Dispatcher is associated with.
Invoke<TResult>(Func<TResult>, DispatcherPriority, CancellationToken)	Executes the specified Func<TResult> synchronously at the specified priority on the thread the Dispatcher is associated with.
Invoke<TResult>(Func<TResult>, DispatcherPriority, CancellationToken, TimeSpan)	Executes the specified Func<TResult> synchronously at the specified priority on the thread the Dispatcher is associated with.

Examples

The following example places a delegate onto a Dispatcher at Normal using Invoke.

// Places the delegate onto the UI Thread's Dispatcher
private void timer_Elapsed(object sender, ElapsedEventArgs e)
{
    // Place delegate on the Dispatcher.
    this.Dispatcher.Invoke(DispatcherPriority.Normal,
        new TimerDispatcherDelegate(TimerWorkItem));
}

' Places the delegate onto the UI Thread's Dispatcher
Private Sub timer_Elapsed(ByVal sender As Object, ByVal e As ElapsedEventArgs)
    ' Place delegate on the Dispatcher.
    Me.Dispatcher.Invoke(DispatcherPriority.Normal, New TimerDispatcherDelegate(AddressOf TimerWorkItem))
End Sub

Remarks

In WPF, only the thread that created a DispatcherObject may access that object. For example, a background thread that is spun off from the main UI thread cannot update the contents of a Button that was created on the UI thread. In order for the background thread to access the Content property of the Button, the background thread must delegate the work to the Dispatcher associated with the UI thread. This is accomplished by using either Invoke or BeginInvoke. Invoke is synchronous and BeginInvoke is asynchronous. The operation is added to the event queue of the Dispatcher at the specified DispatcherPriority.

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Invoke(DispatcherPriority, TimeSpan, Delegate, Object, Object[])

Executes the specified delegate at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.

public:
 System::Object ^ Invoke(System::Windows::Threading::DispatcherPriority priority, TimeSpan timeout, Delegate ^ method, System::Object ^ arg, ... cli::array <System::Object ^> ^ args);

[System.ComponentModel.Browsable(false)]
public object Invoke (System.Windows.Threading.DispatcherPriority priority, TimeSpan timeout, Delegate method, object arg, params object[] args);

[<System.ComponentModel.Browsable(false)>]
member this.Invoke : System.Windows.Threading.DispatcherPriority * TimeSpan * Delegate * obj * obj[] -> obj

Public Function Invoke (priority As DispatcherPriority, timeout As TimeSpan, method As Delegate, arg As Object, ParamArray args As Object()) As Object

Parameters

priority: DispatcherPriority

The priority, relative to the other pending operations in the Dispatcher event queue, with which the specified method is invoked.

timeout: TimeSpan

The maximum amount of time to wait for the operation to start. Once the operation has started, it will complete before this method returns. To specify an infinite wait, use a value of -1. In a same-thread call, any other negative value is converted to -1, resulting in an infinite wait. In a cross-thread call, any other negative value throws an ArgumentOutOfRangeException.

method: Delegate

A delegate to a method that takes multiple arguments, which is pushed onto the Dispatcher event queue.

arg: Object

An object to pass as an argument to the specified method.

args: Object[]

An array of objects to pass as arguments to the specified method.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Attributes: BrowsableAttribute

Exceptions

ArgumentException

priority is equal to Inactive.

InvalidEnumArgumentException

priority is not a valid DispatcherPriority.

ArgumentNullException

method is null.

ArgumentOutOfRangeException

timeout is a negative number other than -1, and this method was invoked across threads.

Remarks

arg can be null if an argument is not needed.

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke(DispatcherPriority, TimeSpan, Delegate, Object)

Executes the specified delegate at the specified priority with the specified argument synchronously on the thread the Dispatcher is associated with.

public:
 System::Object ^ Invoke(System::Windows::Threading::DispatcherPriority priority, TimeSpan timeout, Delegate ^ method, System::Object ^ arg);

[System.ComponentModel.Browsable(false)]
public object Invoke (System.Windows.Threading.DispatcherPriority priority, TimeSpan timeout, Delegate method, object arg);

[<System.ComponentModel.Browsable(false)>]
member this.Invoke : System.Windows.Threading.DispatcherPriority * TimeSpan * Delegate * obj -> obj

Public Function Invoke (priority As DispatcherPriority, timeout As TimeSpan, method As Delegate, arg As Object) As Object

Parameters

priority: DispatcherPriority

The priority, relative to the other pending operations in the Dispatcher event queue, with which the specified method is invoked.

timeout: TimeSpan

method: Delegate

A delegate to a method that takes multiple arguments, which is pushed onto the Dispatcher event queue.

arg: Object

An object to pass as an argument to the given method. This can be null if no arguments are needed.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Attributes: BrowsableAttribute

Exceptions

ArgumentException

priority is equal to Inactive.

InvalidEnumArgumentException

priority is not a valid priority.

ArgumentNullException

method is null.

Remarks

arg can be null if an argument is not needed

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke(DispatcherPriority, Delegate, Object, Object[])

Executes the specified delegate at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.

public:
 System::Object ^ Invoke(System::Windows::Threading::DispatcherPriority priority, Delegate ^ method, System::Object ^ arg, ... cli::array <System::Object ^> ^ args);

[System.ComponentModel.Browsable(false)]
public object Invoke (System.Windows.Threading.DispatcherPriority priority, Delegate method, object arg, params object[] args);

[<System.ComponentModel.Browsable(false)>]
member this.Invoke : System.Windows.Threading.DispatcherPriority * Delegate * obj * obj[] -> obj

Public Function Invoke (priority As DispatcherPriority, method As Delegate, arg As Object, ParamArray args As Object()) As Object

Parameters

priority: DispatcherPriority

The priority, relative to the other pending operations in the Dispatcher event queue, with which the specified method is invoked.

method: Delegate

A delegate to a method that takes multiple arguments, which is pushed onto the Dispatcher event queue.

arg: Object

An object to pass as an argument to the given method.

args: Object[]

An array of objects to pass as arguments to the given method.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Attributes: BrowsableAttribute

Exceptions

ArgumentException

priority is equal to Inactive.

InvalidEnumArgumentException

priority is not a valid priority.

ArgumentNullException

method is null.

Remarks

arg can be null if an argument is not needed

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke(Action, DispatcherPriority, CancellationToken, TimeSpan)

Executes the specified Action synchronously at the specified priority on the thread the Dispatcher is associated with.

public:
 void Invoke(Action ^ callback, System::Windows::Threading::DispatcherPriority priority, System::Threading::CancellationToken cancellationToken, TimeSpan timeout);

public void Invoke (Action callback, System.Windows.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken, TimeSpan timeout);

member this.Invoke : Action * System.Windows.Threading.DispatcherPriority * System.Threading.CancellationToken * TimeSpan -> unit

Public Sub Invoke (callback As Action, priority As DispatcherPriority, cancellationToken As CancellationToken, timeout As TimeSpan)

Parameters

callback: Action

An Action delegate to invoke through the dispatcher.

priority: DispatcherPriority

The priority that determines the order in which the specified callback is invoked relative to the other pending operations in the Dispatcher.

cancellationToken: CancellationToken

An object that indicates whether to cancel the action.

timeout: TimeSpan

Exceptions

ArgumentNullException

callback is null.

ArgumentOutOfRangeException

timeout is a negative number other than -1, and this method was invoked across threads.

InvalidEnumArgumentException

priority is not a valid priority.

OperationCanceledException

The cancellation token was canceled. This exception is stored into the returned task.

Applies to

Invoke(DispatcherPriority, TimeSpan, Delegate)

Executes the specified delegate synchronously at the specified priority and with the specified time-out value on the thread the Dispatcher was created.

public:
 System::Object ^ Invoke(System::Windows::Threading::DispatcherPriority priority, TimeSpan timeout, Delegate ^ method);

[System.ComponentModel.Browsable(false)]
public object Invoke (System.Windows.Threading.DispatcherPriority priority, TimeSpan timeout, Delegate method);

[<System.ComponentModel.Browsable(false)>]
member this.Invoke : System.Windows.Threading.DispatcherPriority * TimeSpan * Delegate -> obj

Public Function Invoke (priority As DispatcherPriority, timeout As TimeSpan, method As Delegate) As Object

Parameters

priority: DispatcherPriority

The priority, relative to the other pending operations in the Dispatcher event queue, with which the specified method is invoked.

timeout: TimeSpan

method: Delegate

The delegate to a method that takes no arguments, which is pushed onto the Dispatcher event queue.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Attributes: BrowsableAttribute

Exceptions

ArgumentNullException

method is null.

ArgumentOutOfRangeException

timeout is a negative number other than -1, and this method was invoked across threads.

ArgumentException

priority is equal to Inactive.

InvalidEnumArgumentException

priority is not a valid priority.

Remarks

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke(DispatcherPriority, Delegate, Object)

Executes the specified delegate at the specified priority with the specified argument synchronously on the thread the Dispatcher is associated with.

public:
 System::Object ^ Invoke(System::Windows::Threading::DispatcherPriority priority, Delegate ^ method, System::Object ^ arg);

[System.ComponentModel.Browsable(false)]
public object Invoke (System.Windows.Threading.DispatcherPriority priority, Delegate method, object arg);

[<System.ComponentModel.Browsable(false)>]
member this.Invoke : System.Windows.Threading.DispatcherPriority * Delegate * obj -> obj

Public Function Invoke (priority As DispatcherPriority, method As Delegate, arg As Object) As Object

Parameters

priority: DispatcherPriority

The priority, relative to the other pending operations in the Dispatcher event queue, with which the specified method is invoked.

method: Delegate

A delegate to a method that takes one argument, which is pushed onto the Dispatcher event queue.

arg: Object

An object to pass as an argument to the given method.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Attributes: BrowsableAttribute

Exceptions

ArgumentException

priority is equal to Inactive.

InvalidEnumArgumentException

priority is not a valid priority.

ArgumentNullException

method is null.

Remarks

arg can be null if an argument is not needed

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke(Delegate, TimeSpan, DispatcherPriority, Object[])

Executes the specified delegate within the designated time span at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.

public:
 System::Object ^ Invoke(Delegate ^ method, TimeSpan timeout, System::Windows::Threading::DispatcherPriority priority, ... cli::array <System::Object ^> ^ args);

public object Invoke (Delegate method, TimeSpan timeout, System.Windows.Threading.DispatcherPriority priority, params object[] args);

member this.Invoke : Delegate * TimeSpan * System.Windows.Threading.DispatcherPriority * obj[] -> obj

Public Function Invoke (method As Delegate, timeout As TimeSpan, priority As DispatcherPriority, ParamArray args As Object()) As Object

Parameters

method: Delegate

A delegate to a method that takes parameters specified in args, which is pushed onto the Dispatcher event queue.

timeout: TimeSpan

priority: DispatcherPriority

The priority, relative to the other pending operations in the Dispatcher event queue, with which the specified method is invoked.

args: Object[]

An array of objects to pass as arguments to the given method. Can be null.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Exceptions

ArgumentNullException

method is null.

ArgumentOutOfRangeException

timeout is a negative number other than -1, and this method was invoked across threads.

ArgumentException

priority is equal to Inactive.

InvalidEnumArgumentException

priority is not a valid priority.

Remarks

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke(Delegate, TimeSpan, Object[])

Executes the specified delegate within the designated time span at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.

public:
 System::Object ^ Invoke(Delegate ^ method, TimeSpan timeout, ... cli::array <System::Object ^> ^ args);

public object Invoke (Delegate method, TimeSpan timeout, params object[] args);

member this.Invoke : Delegate * TimeSpan * obj[] -> obj

Public Function Invoke (method As Delegate, timeout As TimeSpan, ParamArray args As Object()) As Object

Parameters

method: Delegate

A delegate to a method that takes parameters specified in args, which is pushed onto the Dispatcher event queue.

timeout: TimeSpan

The maximum amount of time to wait for the operation to start. However, once the operation starts, it will complete before this method returns. To specify an infinite wait, use a value of -1. In a same-thread call, any other negative value is converted to -1, resulting in an infinite wait. In a cross-thread call, any other negative value throws an ArgumentOutOfRangeException.

args: Object[]

An array of objects to pass as arguments to the given method. Can be null if no arguments are needed.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Exceptions

ArgumentNullException

method is null.

ArgumentOutOfRangeException

timeout is a negative number other than -1, and you're invoking across threads.

Remarks

Invoke is a synchronous operation; therefore, control won't return to the calling object until after the callback returns.

Applies to

Invoke(Action, DispatcherPriority, CancellationToken)

Executes the specified Action synchronously at the specified priority on the thread the Dispatcher is associated with.

public:
 void Invoke(Action ^ callback, System::Windows::Threading::DispatcherPriority priority, System::Threading::CancellationToken cancellationToken);

public void Invoke (Action callback, System.Windows.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken);

member this.Invoke : Action * System.Windows.Threading.DispatcherPriority * System.Threading.CancellationToken -> unit

Public Sub Invoke (callback As Action, priority As DispatcherPriority, cancellationToken As CancellationToken)

Parameters

callback: Action

A delegate to invoke through the dispatcher.

priority: DispatcherPriority

The priority that determines the order in which the specified callback is invoked relative to the other pending operations in the Dispatcher.

cancellationToken: CancellationToken

An object that indicates whether to cancel the action.

Exceptions

OperationCanceledException

The cancellation token was canceled. This exception is stored into the returned task.

Applies to

Invoke(DispatcherPriority, Delegate)

Executes the specified delegate synchronously at the specified priority on the thread that the Dispatcher is associated with.

public:
 System::Object ^ Invoke(System::Windows::Threading::DispatcherPriority priority, Delegate ^ method);

[System.ComponentModel.Browsable(false)]
public object Invoke (System.Windows.Threading.DispatcherPriority priority, Delegate method);

[<System.ComponentModel.Browsable(false)>]
member this.Invoke : System.Windows.Threading.DispatcherPriority * Delegate -> obj

Public Function Invoke (priority As DispatcherPriority, method As Delegate) As Object

Parameters

priority: DispatcherPriority

The priority with which the specified method is invoked, relative to the other pending operations in the Dispatcher event queue.

method: Delegate

A delegate to a method that takes no arguments, which is pushed onto the Dispatcher event queue.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Attributes: BrowsableAttribute

Exceptions

ArgumentException

priority is equal to Inactive.

InvalidEnumArgumentException

priority is not a valid priority.

ArgumentNullException

method is null.

Examples

The following example places a delegate onto a Dispatcher at Normal using Invoke.

// Places the delegate onto the UI Thread's Dispatcher
private void timer_Elapsed(object sender, ElapsedEventArgs e)
{
    // Place delegate on the Dispatcher.
    this.Dispatcher.Invoke(DispatcherPriority.Normal,
        new TimerDispatcherDelegate(TimerWorkItem));
}

' Places the delegate onto the UI Thread's Dispatcher
Private Sub timer_Elapsed(ByVal sender As Object, ByVal e As ElapsedEventArgs)
    ' Place delegate on the Dispatcher.
    Me.Dispatcher.Invoke(DispatcherPriority.Normal, New TimerDispatcherDelegate(AddressOf TimerWorkItem))
End Sub

Remarks

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke(Delegate, Object[])

Executes the specified delegate with the specified arguments synchronously on the thread the Dispatcher is associated with.

public:
 System::Object ^ Invoke(Delegate ^ method, ... cli::array <System::Object ^> ^ args);

public object Invoke (Delegate method, params object[] args);

member this.Invoke : Delegate * obj[] -> obj

Public Function Invoke (method As Delegate, ParamArray args As Object()) As Object

Parameters

method: Delegate

A delegate to a method that takes parameters specified in args, which is pushed onto the Dispatcher event queue.

args: Object[]

An array of objects to pass as arguments to the given method. Can be null.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Remarks

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke(Action, DispatcherPriority)

Executes the specified Action synchronously at the specified priority on the thread the Dispatcher is associated with.

public:
 void Invoke(Action ^ callback, System::Windows::Threading::DispatcherPriority priority);

public void Invoke (Action callback, System.Windows.Threading.DispatcherPriority priority);

member this.Invoke : Action * System.Windows.Threading.DispatcherPriority -> unit

Public Sub Invoke (callback As Action, priority As DispatcherPriority)

Parameters

callback: Action

A delegate to invoke through the dispatcher.

priority: DispatcherPriority

The priority that determines the order in which the specified callback is invoked relative to the other pending operations in the Dispatcher.

Applies to

Invoke(Action)

Executes the specified Action synchronously on the thread the Dispatcher is associated with.

public:
 void Invoke(Action ^ callback);

public void Invoke (Action callback);

member this.Invoke : Action -> unit

Public Sub Invoke (callback As Action)

Parameters

callback: Action

A delegate to invoke through the dispatcher.

Remarks

The default priority is DispatcherPriority.Send.

Applies to

Invoke(Delegate, DispatcherPriority, Object[])

Executes the specified delegate at the specified priority with the specified arguments synchronously on the thread the Dispatcher is associated with.

public:
 System::Object ^ Invoke(Delegate ^ method, System::Windows::Threading::DispatcherPriority priority, ... cli::array <System::Object ^> ^ args);

public object Invoke (Delegate method, System.Windows.Threading.DispatcherPriority priority, params object[] args);

member this.Invoke : Delegate * System.Windows.Threading.DispatcherPriority * obj[] -> obj

Public Function Invoke (method As Delegate, priority As DispatcherPriority, ParamArray args As Object()) As Object

Parameters

method: Delegate

A delegate to a method that takes parameters specified in args, which is pushed onto the Dispatcher event queue.

priority: DispatcherPriority

The priority with which the specified method is invoked, relative to the other pending operations in the Dispatcher event queue.

args: Object[]

An array of objects to pass as arguments to the given method. Can be null.

Returns

Object

The return value from the delegate being invoked or null if the delegate has no return value.

Remarks

Invoke is a synchronous operation; therefore, control will not return to the calling object until after the callback returns.

Applies to

Invoke<TResult>(Func<TResult>)

Executes the specified Func<TResult> synchronously on the thread the Dispatcher is associated with.

public:
generic <typename TResult>
 TResult Invoke(Func<TResult> ^ callback);

public TResult Invoke<TResult> (Func<TResult> callback);

member this.Invoke : Func<'Result> -> 'Result

Public Function Invoke(Of TResult) (callback As Func(Of TResult)) As TResult

Type Parameters

TResult

The return value type of the specified delegate.

Parameters

callback: Func<TResult>

A delegate to invoke through the dispatcher.

Returns

TResult

The value returned by callback.

Applies to

Invoke<TResult>(Func<TResult>, DispatcherPriority)

Executes the specified Func<TResult> synchronously at the specified priority on the thread the Dispatcher is associated with.

public:
generic <typename TResult>
 TResult Invoke(Func<TResult> ^ callback, System::Windows::Threading::DispatcherPriority priority);

public TResult Invoke<TResult> (Func<TResult> callback, System.Windows.Threading.DispatcherPriority priority);

member this.Invoke : Func<'Result> * System.Windows.Threading.DispatcherPriority -> 'Result

Public Function Invoke(Of TResult) (callback As Func(Of TResult), priority As DispatcherPriority) As TResult

Type Parameters

TResult

The return value type of the specified delegate.

Parameters

callback: Func<TResult>

A delegate to invoke through the dispatcher.

priority: DispatcherPriority

The priority that determines the order in which the specified callback is invoked relative to the other pending operations in the Dispatcher.

Returns

TResult

The value returned by callback.

Applies to

Invoke<TResult>(Func<TResult>, DispatcherPriority, CancellationToken)

Executes the specified Func<TResult> synchronously at the specified priority on the thread the Dispatcher is associated with.

public:
generic <typename TResult>
 TResult Invoke(Func<TResult> ^ callback, System::Windows::Threading::DispatcherPriority priority, System::Threading::CancellationToken cancellationToken);

public TResult Invoke<TResult> (Func<TResult> callback, System.Windows.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken);

member this.Invoke : Func<'Result> * System.Windows.Threading.DispatcherPriority * System.Threading.CancellationToken -> 'Result

Public Function Invoke(Of TResult) (callback As Func(Of TResult), priority As DispatcherPriority, cancellationToken As CancellationToken) As TResult

Type Parameters

TResult

The return value type of the specified delegate.

Parameters

callback: Func<TResult>

A delegate to invoke through the dispatcher.

priority: DispatcherPriority

The priority that determines the order in which the specified callback is invoked relative to the other pending operations in the Dispatcher.

cancellationToken: CancellationToken

An object that indicates whether to cancel the operation.

Returns

TResult

The value returned by callback.

Exceptions

OperationCanceledException

The cancellation token was canceled. This exception is stored into the returned task.

Applies to

Invoke<TResult>(Func<TResult>, DispatcherPriority, CancellationToken, TimeSpan)

Executes the specified Func<TResult> synchronously at the specified priority on the thread the Dispatcher is associated with.

public:
generic <typename TResult>
 TResult Invoke(Func<TResult> ^ callback, System::Windows::Threading::DispatcherPriority priority, System::Threading::CancellationToken cancellationToken, TimeSpan timeout);

public TResult Invoke<TResult> (Func<TResult> callback, System.Windows.Threading.DispatcherPriority priority, System.Threading.CancellationToken cancellationToken, TimeSpan timeout);

member this.Invoke : Func<'Result> * System.Windows.Threading.DispatcherPriority * System.Threading.CancellationToken * TimeSpan -> 'Result

Public Function Invoke(Of TResult) (callback As Func(Of TResult), priority As DispatcherPriority, cancellationToken As CancellationToken, timeout As TimeSpan) As TResult

Type Parameters

TResult

The return value type of the specified delegate.

Parameters

callback: Func<TResult>

A delegate to invoke through the dispatcher.

priority: DispatcherPriority

The priority that determines the order in which the specified callback is invoked relative to the other pending operations in the Dispatcher.

cancellationToken: CancellationToken

An object that indicates whether to cancel the operation.

timeout: TimeSpan

Returns

TResult

The value returned by callback.

Exceptions

ArgumentNullException

callback is null.

ArgumentOutOfRangeException

timeout is a negative number other than -1, and the method was invoked across threads.

InvalidEnumArgumentException

priority is not a valid priority.

OperationCanceledException

The cancellation token was canceled. This exception is stored into the returned task.

Applies to

แชร์ผ่าน

Dispatcher.Invoke Method

Definition

Overloads

Examples

Remarks

Invoke(DispatcherPriority, TimeSpan, Delegate, Object, Object[])

Parameters

Returns

Exceptions

Remarks

Applies to

Invoke(DispatcherPriority, TimeSpan, Delegate, Object)

Parameters

Returns

Exceptions

Remarks

Applies to

Invoke(DispatcherPriority, Delegate, Object, Object[])

Parameters

Returns

Exceptions

Remarks

Applies to

Invoke(Action, DispatcherPriority, CancellationToken, TimeSpan)

Parameters

Exceptions

Applies to

Invoke(DispatcherPriority, TimeSpan, Delegate)

Parameters

Returns

Exceptions

Remarks

Applies to

Invoke(DispatcherPriority, Delegate, Object)

Parameters

Returns

Exceptions

Remarks

Applies to

Invoke(Delegate, TimeSpan, DispatcherPriority, Object[])

Parameters

Returns

Exceptions

Remarks

Applies to

Invoke(Delegate, TimeSpan, Object[])

Parameters

Returns

Exceptions

Remarks

Applies to

Invoke(Action, DispatcherPriority, CancellationToken)

Parameters

Exceptions

Applies to

Invoke(DispatcherPriority, Delegate)

Parameters

Returns

Exceptions

Examples

Remarks

Applies to

Invoke(Delegate, Object[])

Parameters

Returns

Remarks

Applies to

Invoke(Action, DispatcherPriority)

Parameters

Applies to

Invoke(Action)

Parameters

Remarks

Applies to

Invoke(Delegate, DispatcherPriority, Object[])

Parameters

Returns

Remarks

Applies to