Control.Invoke Control.Invoke Control.Invoke Control.Invoke Method

Definición

Ejecuta un delegado en el subproceso que posee el identificador de ventana subyacente del control.Executes a delegate on the thread that owns the control's underlying window handle.

Sobrecargas

Invoke(Delegate) Invoke(Delegate) Invoke(Delegate) Invoke(Delegate)

Ejecuta el delegado especificado en el subproceso que posee el identificador de ventana subyacente del control.Executes the specified delegate on the thread that owns the control's underlying window handle.

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

Ejecuta el delegado especificado en el subproceso que posee el identificador de la ventana subyacente del control, con la lista de argumentos especificada.Executes the specified delegate, on the thread that owns the control's underlying window handle, with the specified list of arguments.

Invoke(Delegate) Invoke(Delegate) Invoke(Delegate) Invoke(Delegate)

Ejecuta el delegado especificado en el subproceso que posee el identificador de ventana subyacente del control.Executes the specified delegate on the thread that owns the control's underlying window handle.

public:
 System::Object ^ Invoke(Delegate ^ method);
public object Invoke (Delegate method);
member this.Invoke : Delegate -> obj
Public Function Invoke (method As Delegate) As Object

Parámetros

method
Delegate Delegate Delegate Delegate

Delegado que contiene un método al que se va a llamar en el contexto del subproceso del control.A delegate that contains a method to be called in the control's thread context.

Devoluciones

Valor devuelto desde el delegado al que se ha invocado o null si el delegado no devuelve ningún valor.The return value from the delegate being invoked, or null if the delegate has no return value.

Ejemplos

En el ejemplo de código siguiente se muestran controles que contienen un delegado.The following code example shows controls that contain a delegate. El delegado encapsula un método que agrega elementos al cuadro de lista y este método se ejecuta en el subproceso que posee el identificador subyacente del formulario.The delegate encapsulates a method that adds items to the list box, and this method is executed on the thread that owns the underlying handle of the form. Cuando el usuario hace clic en el botón, Invoke ejecuta el delegado.When the user clicks on the button, Invoke runs the delegate.

/*
The following example demonstrates the 'Invoke(Delegate*)' method of 'Control class.
A 'ListBox' and a 'Button' control are added to a form, containing a delegate
which encapsulates a method that adds items to the listbox.This function is executed
on the thread that owns the underlying handle of the form. When user clicks on button
the above delegate is executed using 'Invoke' method.
*/

#using <System.dll>
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;
using namespace System::Threading;

public ref class MyFormControl: public Form
{
public:
   delegate void AddListItem();
   AddListItem^ myDelegate;

private:
   Button^ myButton;
   Thread^ myThread;
   ListBox^ myListBox;

public:
   MyFormControl();
   void AddListItemMethod()
   {
      String^ myItem;
      for ( int i = 1; i < 6; i++ )
      {
         myItem = "MyListItem {0}",i;
         myListBox->Items->Add( myItem );
         myListBox->Update();
         Thread::Sleep( 300 );
      }
   }

private:
   void Button_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      myThread = gcnew Thread( gcnew ThreadStart( this, &MyFormControl::ThreadFunction ) );
      myThread->Start();
   }

   void ThreadFunction();
};


// The following code assumes a 'ListBox' and a 'Button' control are added to a form,
// containing a delegate which encapsulates a method that adds items to the listbox.
public ref class MyThreadClass
{
private:
   MyFormControl^ myFormControl1;

public:
   MyThreadClass( MyFormControl^ myForm )
   {
      myFormControl1 = myForm;
   }

   void Run()
   {
      // Execute the specified delegate on the thread that owns
      // 'myFormControl1' control's underlying window handle.
      myFormControl1->Invoke( myFormControl1->myDelegate );
   }
};


MyFormControl::MyFormControl()
{
   myButton = gcnew Button;
   myListBox = gcnew ListBox;
   myButton->Location = Point( 72, 160 );
   myButton->Size = System::Drawing::Size( 152, 32 );
   myButton->TabIndex = 1;
   myButton->Text = "Add items in list box";
   myButton->Click += gcnew EventHandler( this, &MyFormControl::Button_Click );
   myListBox->Location = Point( 48, 32 );
   myListBox->Name = "myListBox";
   myListBox->Size = System::Drawing::Size( 200, 95 );
   myListBox->TabIndex = 2;
   ClientSize = System::Drawing::Size( 292, 273 );
   array<Control^>^ temp0 = {myListBox,myButton};
   Controls->AddRange( temp0 );
   Text = " 'Control_Invoke' example";
   myDelegate = gcnew AddListItem( this, &MyFormControl::AddListItemMethod );
}

void MyFormControl::ThreadFunction()
{
   MyThreadClass^ myThreadClassObject = gcnew MyThreadClass( this );
   myThreadClassObject->Run();
}

int main()
{
   MyFormControl^ myForm = gcnew MyFormControl;
   myForm->ShowDialog();
}
/*
The following example demonstrates the 'Invoke(Delegate)' method of 'Control class.
A 'ListBox' and a 'Button' control are added to a form, containing a delegate
which encapsulates a method that adds items to the listbox.This function is executed
on the thread that owns the underlying handle of the form. When user clicks on button
the above delegate is executed using 'Invoke' method.


*/

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Threading;

   public class MyFormControl : Form
   {
      public delegate void AddListItem();
      public AddListItem myDelegate;
      private Button myButton;
      private Thread myThread;
      private ListBox myListBox;
      public MyFormControl()
      {
         myButton = new Button();
         myListBox = new ListBox();
         myButton.Location = new Point(72, 160);
         myButton.Size = new Size(152, 32);
         myButton.TabIndex = 1;
         myButton.Text = "Add items in list box";
         myButton.Click += new EventHandler(Button_Click);
         myListBox.Location = new Point(48, 32);
         myListBox.Name = "myListBox";
         myListBox.Size = new Size(200, 95);
         myListBox.TabIndex = 2;
         ClientSize = new Size(292, 273);
         Controls.AddRange(new Control[] {myListBox,myButton});
         Text = " 'Control_Invoke' example";
         myDelegate = new AddListItem(AddListItemMethod);
      }
      static void Main()
      {
         MyFormControl myForm = new MyFormControl();
         myForm.ShowDialog();
      }
      public void AddListItemMethod()
      {
         String myItem;
         for(int i=1;i<6;i++)
         {
            myItem = "MyListItem" + i.ToString();
            myListBox.Items.Add(myItem);
            myListBox.Update();
            Thread.Sleep(300);
         }
      }
      private void Button_Click(object sender, EventArgs e)
      {
         myThread = new Thread(new ThreadStart(ThreadFunction));
         myThread.Start();
      }
      private void ThreadFunction()
      {
         MyThreadClass myThreadClassObject  = new MyThreadClass(this);
         myThreadClassObject.Run();
      }
   }

// The following code assumes a 'ListBox' and a 'Button' control are added to a form, 
// containing a delegate which encapsulates a method that adds items to the listbox.

   public class MyThreadClass
   {
      MyFormControl myFormControl1;
      public MyThreadClass(MyFormControl myForm)
      {
         myFormControl1 = myForm;
      }

      public void Run()
      {
         // Execute the specified delegate on the thread that owns
         // 'myFormControl1' control's underlying window handle.
         myFormControl1.Invoke(myFormControl1.myDelegate);
      }
   }
' The following example demonstrates the 'Invoke(Delegate)' method of 'Control class.
' A 'ListBox' and a 'Button' control are added to a form, containing a delegate
' which encapsulates a method that adds items to the listbox.This function is executed
' on the thread that owns the underlying handle of the form. When user clicks on button
' the above delegate is executed using 'Invoke' method.

Imports System.Drawing
Imports System.Windows.Forms
Imports System.Threading

Public Class MyFormControl
   Inherits Form

   Delegate Sub AddListItem()
   Public myDelegate As AddListItem
   Private myButton As Button
   Private myThread As Thread
   Private myListBox As ListBox

   Public Sub New()
      myButton = New Button()
      myListBox = New ListBox()
      myButton.Location = New Point(72, 160)
      myButton.Size = New Size(152, 32)
      myButton.TabIndex = 1
      myButton.Text = "Add items in list box"
      AddHandler myButton.Click, AddressOf Button_Click
      myListBox.Location = New Point(48, 32)
      myListBox.Name = "myListBox"
      myListBox.Size = New Size(200, 95)
      myListBox.TabIndex = 2
      ClientSize = New Size(292, 273)
      Controls.AddRange(New Control() {myListBox, myButton})
      Text = " 'Control_Invoke' example"
      myDelegate = New AddListItem(AddressOf AddListItemMethod)
   End Sub

   Shared Sub Main()
      Dim myForm As New MyFormControl()
      myForm.ShowDialog()
   End Sub

   Public Sub AddListItemMethod()
      Dim myItem As String
      Dim i As Integer
      For i = 1 To 5
         myItem = "MyListItem" + i.ToString()
         myListBox.Items.Add(myItem)
         myListBox.Update()
         Thread.Sleep(300)
      Next i
   End Sub

   Private Sub Button_Click(sender As Object, e As EventArgs)
      myThread = New Thread(New ThreadStart(AddressOf ThreadFunction))
      myThread.Start()
   End Sub

   Private Sub ThreadFunction()
      Dim myThreadClassObject As New MyThreadClass(Me)
      myThreadClassObject.Run()
   End Sub
End Class 'MyFormControl


' The following code assumes a 'ListBox' and a 'Button' control are added to a form, 
' containing a delegate which encapsulates a method that adds items to the listbox.
Public Class MyThreadClass
   Private myFormControl1 As MyFormControl

   Public Sub New(myForm As MyFormControl)
      myFormControl1 = myForm
   End Sub

   Public Sub Run()
      ' Execute the specified delegate on the thread that owns
      ' 'myFormControl1' control's underlying window handle.
      myFormControl1.Invoke(myFormControl1.myDelegate)
   End Sub

End Class 'MyThreadClass

Comentarios

Los delegados son similares a los punteros C++ de función en C o lenguajes.Delegates are similar to function pointers in C or C++ languages. Los delegados encapsulan una referencia a un método dentro de un objeto delegado.Delegates encapsulate a reference to a method inside a delegate object. A continuación, el objeto delegado se puede pasar al código que llama al método al que se hace referencia y el método que se va a invocar se puede desconocer en tiempo de compilación.The delegate object can then be passed to code that calls the referenced method, and the method to be invoked can be unknown at compile time. A diferencia de los punteros de función C++de C o, los delegados están orientados a objetos, tienen seguridad de tipos y son más seguros.Unlike function pointers in C or C++, delegates are object-oriented, type-safe, and more secure.

El Invoke método busca en la cadena primaria del control hasta que encuentra un control o formulario que tiene un identificador de ventana si el identificador de ventana subyacente del control actual todavía no existe.The Invoke method searches up the control's parent chain until it finds a control or form that has a window handle if the current control's underlying window handle does not exist yet. Si no se encuentra ningún identificador adecuado, el Invoke método producirá una excepción.If no appropriate handle can be found, the Invoke method will throw an exception. Las excepciones que se producen durante la llamada se propagan de nuevo al autor de la llamada.Exceptions that are raised during the call will be propagated back to the caller.

Nota

Además de InvokeRequired la propiedad, hay cuatro métodos en un control que son seguros para subprocesos Invoke: BeginInvoke, EndInvoke, y CreateGraphics si ya se ha creado el identificador del control.In addition to the InvokeRequired property, there are four methods on a control that are thread safe: Invoke, BeginInvoke, EndInvoke, and CreateGraphics if the handle for the control has already been created. La CreateGraphics llamada a antes de que el identificador del control se haya creado en un subproceso en segundo plano puede producir llamadas cruzadas no válidas.Calling CreateGraphics before the control's handle has been created on a background thread can cause illegal cross thread calls. Para todas las demás llamadas al método, debe usar uno de los métodos de invocación para calcular las referencias de la llamada al subproceso del control.For all other method calls, you should use one of the invoke methods to marshal the call to the control's thread.

El delegado puede ser una instancia de EventHandler, en cuyo caso el parámetro Sender contendrá este control y el parámetro EventArgs.Emptyde evento contendrá.The delegate can be an instance of EventHandler, in which case the sender parameter will contain this control, and the event parameter will contain EventArgs.Empty. El delegado también puede ser una instancia de MethodInvokero cualquier otro delegado que toma una lista de parámetros void.The delegate can also be an instance of MethodInvoker, or any other delegate that takes a void parameter list. Una llamada a un EventHandler delegado MethodInvoker o será más rápida que una llamada a otro tipo de delegado.A call to an EventHandler or MethodInvoker delegate will be faster than a call to another type of delegate.

Nota

Podría producirse una excepción si el subproceso que debería procesar el mensaje ya no está activo.An exception might be thrown if the thread that should process the message is no longer active.

Consulte también:

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

Ejecuta el delegado especificado en el subproceso que posee el identificador de la ventana subyacente del control, con la lista de argumentos especificada.Executes the specified delegate, on the thread that owns the control's underlying window handle, with the specified list of arguments.

public:
 virtual System::Object ^ Invoke(Delegate ^ method, cli::array <System::Object ^> ^ args);
public object Invoke (Delegate method, object[] args);
abstract member Invoke : Delegate * obj[] -> obj
override this.Invoke : Delegate * obj[] -> obj
Public Function Invoke (method As Delegate, args As Object()) As Object

Parámetros

method
Delegate Delegate Delegate Delegate

Delegado de un método que obtiene los parámetros del mismo número y tipo que los incluidos en el parámetro args.A delegate to a method that takes parameters of the same number and type that are contained in the args parameter.

args
Object[]

Matriz de objetos cuyos valores se pasan como argumentos al método especificado.An array of objects to pass as arguments to the specified method. Este parámetro puede ser null si el método no toma ningún argumento.This parameter can be null if the method takes no arguments.

Devoluciones

Object que contiene el valor devuelto por el delegado al que se ha invocado, o null si el delegado no devuelve ningún valor.An Object that contains the return value from the delegate being invoked, or null if the delegate has no return value.

Implementaciones

Ejemplos

En el ejemplo de código siguiente se muestran controles que contienen un delegado.The following code example shows controls that contain a delegate. El delegado encapsula un método que agrega elementos al cuadro de lista, y este método se ejecuta en el subproceso que posee el identificador subyacente del formulario, utilizando los argumentos especificados.The delegate encapsulates a method that adds items to the list box, and this method is executed on the thread that owns the underlying handle of the form, using the specified arguments. Cuando el usuario hace clic en el botón, Invoke ejecuta el delegado.When the user clicks on the button, Invoke runs the delegate.

using namespace System;
using namespace System::Drawing;
using namespace System::ComponentModel;
using namespace System::Windows::Forms;
using namespace System::Threading;
ref class MyFormControl: public Form
{
public:
   delegate void AddListItem( String^ myString );
   AddListItem^ myDelegate;

private:
   Button^ myButton;
   Thread^ myThread;
   ListBox^ myListBox;

public:
   MyFormControl();
   void AddListItemMethod( String^ myString );

private:
   void Button_Click( Object^ sender, EventArgs^ e );
   void ThreadFunction();
};

ref class MyThreadClass
{
private:
   MyFormControl^ myFormControl1;

public:
   MyThreadClass( MyFormControl^ myForm )
   {
      myFormControl1 = myForm;
   }

   String^ myString;
   void Run()
   {
      for ( int i = 1; i <= 5; i++ )
      {
         myString = String::Concat( "Step number ", i, " executed" );
         Thread::Sleep( 400 );
         
         // Execute the specified delegate on the thread that owns
         // 'myFormControl1' control's underlying window handle with
         // the specified list of arguments.
         array<Object^>^myStringArray = {myString};
         myFormControl1->Invoke( myFormControl1->myDelegate, myStringArray );

      }
   }

};

MyFormControl::MyFormControl()
{
   myButton = gcnew Button;
   myListBox = gcnew ListBox;
   myButton->Location = Point(72,160);
   myButton->Size = System::Drawing::Size( 152, 32 );
   myButton->TabIndex = 1;
   myButton->Text = "Add items in list box";
   myButton->Click += gcnew EventHandler( this, &MyFormControl::Button_Click );
   myListBox->Location = Point(48,32);
   myListBox->Name = "myListBox";
   myListBox->Size = System::Drawing::Size( 200, 95 );
   myListBox->TabIndex = 2;
   ClientSize = System::Drawing::Size( 292, 273 );
   array<Control^>^formControls = {myListBox,myButton};
   Controls->AddRange( formControls );
   Text = " 'Control_Invoke' example ";
   myDelegate = gcnew AddListItem( this, &MyFormControl::AddListItemMethod );
}

void MyFormControl::AddListItemMethod( String^ myString )
{
   myListBox->Items->Add( myString );
}

void MyFormControl::Button_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
{
   myThread = gcnew Thread( gcnew ThreadStart( this, &MyFormControl::ThreadFunction ) );
   myThread->Start();
}

void MyFormControl::ThreadFunction()
{
   MyThreadClass^ myThreadClassObject = gcnew MyThreadClass( this );
   myThreadClassObject->Run();
}

int main()
{
   MyFormControl^ myForm = gcnew MyFormControl;
   myForm->ShowDialog();
}

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Threading;

   public class MyFormControl : Form
   {
      public delegate void AddListItem(String myString);
      public AddListItem myDelegate;
      private Button myButton;
      private Thread myThread;
      private ListBox myListBox;
      public MyFormControl()
      {
         myButton = new Button();
         myListBox = new ListBox();
         myButton.Location = new Point(72, 160);
         myButton.Size = new Size(152, 32);
         myButton.TabIndex = 1;
         myButton.Text = "Add items in list box";
         myButton.Click += new EventHandler(Button_Click);
         myListBox.Location = new Point(48, 32);
         myListBox.Name = "myListBox";
         myListBox.Size = new Size(200, 95);
         myListBox.TabIndex = 2;
         ClientSize = new Size(292, 273);
         Controls.AddRange(new Control[] {myListBox,myButton});
         Text = " 'Control_Invoke' example ";
         myDelegate = new AddListItem(AddListItemMethod);
      }
      static void Main()
      {
         MyFormControl myForm = new MyFormControl();
         myForm.ShowDialog();
      }
      public void AddListItemMethod(String myString)
      {
            myListBox.Items.Add(myString);
      }
      private void Button_Click(object sender, EventArgs e)
      {
         myThread = new Thread(new ThreadStart(ThreadFunction));
         myThread.Start();
      }
      private void ThreadFunction()
      {
         MyThreadClass myThreadClassObject  = new MyThreadClass(this);
         myThreadClassObject.Run();
      }
   }
   public class MyThreadClass
   {
      MyFormControl myFormControl1;
      public MyThreadClass(MyFormControl myForm)
      {
         myFormControl1 = myForm;
      }
      String myString;

      public void Run()
      {


         for (int i = 1; i <= 5; i++)
         {
            myString = "Step number " + i.ToString() + " executed";
            Thread.Sleep(400);
            // Execute the specified delegate on the thread that owns
            // 'myFormControl1' control's underlying window handle with
            // the specified list of arguments.
            myFormControl1.Invoke(myFormControl1.myDelegate,
                                   new Object[] {myString});
         }
      }
   }
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Threading

Public Class MyFormControl
   Inherits Form

   Delegate Sub AddListItem(myString As String)
   Public myDelegate As AddListItem
   Private myButton As Button
   Private myThread As Thread
   Private myListBox As ListBox

   Public Sub New()
      myButton = New Button()
      myListBox = New ListBox()
      myButton.Location = New Point(72, 160)
      myButton.Size = New Size(152, 32)
      myButton.TabIndex = 1
      myButton.Text = "Add items in list box"
      AddHandler myButton.Click, AddressOf Button_Click
      myListBox.Location = New Point(48, 32)
      myListBox.Name = "myListBox"
      myListBox.Size = New Size(200, 95)
      myListBox.TabIndex = 2
      ClientSize = New Size(292, 273)
      Controls.AddRange(New Control() {myListBox, myButton})
      Text = " 'Control_Invoke' example "
      myDelegate = New AddListItem(AddressOf AddListItemMethod)
   End Sub

   Shared Sub Main()
      Dim myForm As New MyFormControl()
      myForm.ShowDialog()
   End Sub

   Public Sub AddListItemMethod(myString As String)
      myListBox.Items.Add(myString)
   End Sub

   Private Sub Button_Click(sender As Object, e As EventArgs)
      myThread = New Thread(New ThreadStart(AddressOf ThreadFunction))
      myThread.Start()
   End Sub

   Private Sub ThreadFunction()
      Dim myThreadClassObject As New MyThreadClass(Me)
      myThreadClassObject.Run()
   End Sub
End Class 'MyFormControl

Public Class MyThreadClass
   Private myFormControl1 As MyFormControl

   Public Sub New(myForm As MyFormControl)
      myFormControl1 = myForm
   End Sub
   Private myString As String

   Public Sub Run()

      Dim i As Integer
      For i = 1 To 5
         myString = "Step number " + i.ToString() + " executed"
         Thread.Sleep(400)
         ' Execute the specified delegate on the thread that owns
         ' 'myFormControl1' control's underlying window handle with
         ' the specified list of arguments.
         myFormControl1.Invoke(myFormControl1.myDelegate, New Object() {myString})
      Next i

   End Sub
End Class 'MyThreadClass

Comentarios

Los delegados son similares a los punteros C++ de función en C o lenguajes.Delegates are similar to function pointers in C or C++ languages. Los delegados encapsulan una referencia a un método dentro de un objeto delegado.Delegates encapsulate a reference to a method inside a delegate object. A continuación, el objeto delegado se puede pasar al código que llama al método al que se hace referencia y el método que se va a invocar se puede desconocer en tiempo de compilación.The delegate object can then be passed to code that calls the referenced method, and the method to be invoked can be unknown at compile time. A diferencia de los punteros de función C++de C o, los delegados están orientados a objetos, tienen seguridad de tipos y son más seguros.Unlike function pointers in C or C++, delegates are object-oriented, type-safe, and more secure.

Si el identificador del control no existe todavía, este método busca en la cadena primaria del control hasta que encuentra un control o formulario que tiene un identificador de ventana.If the control's handle does not exist yet, this method searches up the control's parent chain until it finds a control or form that does have a window handle. Si no se encuentra ningún identificador adecuado, este método produce una excepción.If no appropriate handle can be found, this method throws an exception. Las excepciones que se producen durante la llamada se propagan de nuevo al autor de la llamada.Exceptions that are raised during the call will be propagated back to the caller.

Nota

Además de InvokeRequired la propiedad, hay cuatro métodos en un control que son seguros para subprocesos Invoke: BeginInvoke, EndInvoke, y CreateGraphics si ya se ha creado el identificador del control.In addition to the InvokeRequired property, there are four methods on a control that are thread safe: Invoke, BeginInvoke, EndInvoke, and CreateGraphics if the handle for the control has already been created. La CreateGraphics llamada a antes de que el identificador del control se haya creado en un subproceso en segundo plano puede producir llamadas cruzadas no válidas.Calling CreateGraphics before the control's handle has been created on a background thread can cause illegal cross thread calls. Para todas las demás llamadas al método, debe usar uno de los métodos de invocación para calcular las referencias de la llamada al subproceso del control.For all other method calls, you should use one of the invoke methods to marshal the call to the control's thread.

El delegado puede ser una instancia de EventHandler, en cuyo caso el parámetro Sender contendrá este control y el parámetro EventArgs.Emptyde evento contendrá.The delegate can be an instance of EventHandler, in which case the sender parameter will contain this control, and the event parameter will contain EventArgs.Empty. El delegado también puede ser una instancia de MethodInvokero cualquier otro delegado que toma una lista de parámetros void.The delegate can also be an instance of MethodInvoker, or any other delegate that takes a void parameter list. Una llamada a un EventHandler delegado MethodInvoker o será más rápida que una llamada a otro tipo de delegado.A call to an EventHandler or MethodInvoker delegate will be faster than a call to another type of delegate.

Nota

Podría producirse una excepción si el subproceso que debería procesar el mensaje ya no está activo.An exception might be thrown if the thread that should process the message is no longer active.

Consulte también:

Se aplica a