Control.OnControlAdded-Methode

Artikel
08/20/2007

Löst das ControlAdded-Ereignis aus.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

Syntax

'Declaration
Protected Overridable Sub OnControlAdded ( _
    e As ControlEventArgs _
)
'Usage
Dim e As ControlEventArgs

Me.OnControlAdded(e)

protected virtual void OnControlAdded (
    ControlEventArgs e
)

protected:
virtual void OnControlAdded (
    ControlEventArgs^ e
)

protected void OnControlAdded (
    ControlEventArgs e
)

protected function OnControlAdded (
    e : ControlEventArgs
)

Parameter

e
Eine Instanz von ControlEventArgs, die die Ereignisdaten enthält.

Hinweise

Wird aufgerufen, wenn ein untergeordnetes Steuerelement diesem Steuerelement hinzugefügt wird.

Durch das Auslösen eines Ereignisses wird der Ereignishandler über einen Delegaten aufgerufen. Weitere Informationen finden Sie unter Auslösen eines Ereignisses.

Die OnControlAdded-Methode ermöglicht es auch abgeleiteten Klassen, das Ereignis ohne Anfügen eines Delegaten zu behandeln. Dies ist das bevorzugte Verfahren für die Behandlung des Ereignisses in einer abgeleiteten Klasse.

Hinweise für Erben Wenn Sie OnControlAdded in einer abgeleiteten Klasse überschreiben, müssen Sie die OnControlAdded-Methode der Basisklasse aufrufen, sodass registrierte Delegaten das Ereignis empfangen.

Beispiel

Im folgenden Codebeispiel wird mithilfe von ControlAdded einem Formular ein Steuerelement hinzugefügt und der Name des hinzugefügten Steuerelements in einer MessageBox angezeigt.

' This example demonstrates the use of the ControlAdded and
' ControlRemoved events. This example assumes that two Button controls 
' are added to the form and connected to the addControl_Click and 
' removeControl_Click event-handler methods.
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
    ' Connect the ControlRemoved and ControlAdded event handlers to the event-handler methods.
    ' ControlRemoved and ControlAdded are not available at design time.
    AddHandler Me.ControlRemoved, AddressOf Me.Control_Removed
    AddHandler Me.ControlAdded, AddressOf Me.Control_Added
End Sub 'Form1_Load


Private Sub Control_Added(ByVal sender As Object, ByVal e As System.Windows.Forms.ControlEventArgs)
    MessageBox.Show(("The control named " + e.Control.Name + " has been added to the form."))
End Sub


Private Sub Control_Removed(ByVal sender As Object, ByVal e As System.Windows.Forms.ControlEventArgs)
    MessageBox.Show(("The control named " + e.Control.Name + " has been removed from the form."))
End Sub


' Click event handler for a Button control. Adds a TextBox to the form.
Private Sub addControl_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles button1.Click
    ' Create a new TextBox control and add it to the form.
    Dim textBox1 As New TextBox()
    textBox1.Size = New Size(100, 10)
    textBox1.Location = New Point(10, 10)
    ' Name the control in order to remove it later. 
    ' The name must be specified if a control is added at run time.
    textBox1.Name = "textBox1"

    ' Add the control to the form's control collection.
    Me.Controls.Add(textBox1)
End Sub


' Click event handler for a Button control.
' Removes the previously added TextBox from the form.
Private Sub removeControl_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles button2.Click
    ' Loop through all controls in the form's control collection.
    Dim tempCtrl As Control
    For Each tempCtrl In Me.Controls
        ' Determine whether the control is textBox1,
        ' and if it is, remove it.
        If tempCtrl.Name = "textBox1" Then
            Me.Controls.Remove(tempCtrl)
        End If
    Next tempCtrl
End Sub

// This example demonstrates the use of the ControlAdded and
// ControlRemoved events. This example assumes that two Button controls
// are added to the form and connected to the addControl_Click and
// removeControl_Click event-handler methods.
private void Form1_Load(object sender, System.EventArgs e)
{
    // Connect the ControlRemoved and ControlAdded event handlers
    // to the event-handler methods.
    // ControlRemoved and ControlAdded are not available at design time.
    this.ControlRemoved += new System.Windows.Forms.ControlEventHandler(this.Control_Removed);
    this.ControlAdded += new System.Windows.Forms.ControlEventHandler(this.Control_Added);
}

private void Control_Added(object sender, System.Windows.Forms.ControlEventArgs e)
{
    MessageBox.Show("The control named " + e.Control.Name + " has been added to the form.");
}

private void Control_Removed(object sender, System.Windows.Forms.ControlEventArgs e)
{
    MessageBox.Show("The control named " + e.Control.Name + " has been removed from the form.");
}

// Click event handler for a Button control. Adds a TextBox to the form.
private void addControl_Click(object sender, System.EventArgs e)
{
    // Create a new TextBox control and add it to the form.
    TextBox textBox1 = new TextBox();
    textBox1.Size = new Size(100,10);
    textBox1.Location = new Point(10,10);
    // Name the control in order to remove it later. The name must be specified
    // if a control is added at run time.
    textBox1.Name = "textBox1";

    // Add the control to the form's control collection.
    this.Controls.Add(textBox1);
}

// Click event handler for a Button control.
// Removes the previously added TextBox from the form.
private void removeControl_Click(object sender, System.EventArgs e)
{
    // Loop through all controls in the form's control collection.
    foreach (Control tempCtrl in this.Controls)
    {
        // Determine whether the control is textBox1,
        // and if it is, remove it.
        if (tempCtrl.Name == "textBox1")
        {
            this.Controls.Remove(tempCtrl);
        }
    }
}

   // This example demonstrates the use of the ControlAdded and
   // ControlRemoved events. This example assumes that two Button controls
   // are added to the form and connected to the addControl_Click and
   // removeControl_Click event-handler methods.
private:
   void Form1_Load( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Connect the ControlRemoved and ControlAdded event handlers
      // to the event-handler methods.
      // ControlRemoved and ControlAdded are not available at design time.
      this->ControlRemoved += gcnew System::Windows::Forms::ControlEventHandler( this, &Form1::Control_Removed );
      this->ControlAdded += gcnew System::Windows::Forms::ControlEventHandler( this, &Form1::Control_Added );
   }

   void Control_Added( Object^ /*sender*/, System::Windows::Forms::ControlEventArgs^ e )
   {
      MessageBox::Show( String::Format( "The control named {0} has been added to the form.", e->Control->Name ) );
   }

   void Control_Removed( Object^ /*sender*/, System::Windows::Forms::ControlEventArgs^ e )
   {
      MessageBox::Show( String::Format( "The control named {0} has been removed from the form.", e->Control->Name ) );
   }

   // Click event handler for a Button control. Adds a TextBox to the form.
   void addControl_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Create a new TextBox control and add it to the form.
      TextBox^ textBox1 = gcnew TextBox;
      textBox1->Size = System::Drawing::Size( 100, 10 );
      textBox1->Location = Point(10,10);

      // Name the control in order to remove it later. The name must be specified
      // if a control is added at run time.
      textBox1->Name = "textBox1";

      // Add the control to the form's control collection.
      this->Controls->Add( textBox1 );
   }

   // Click event handler for a Button control.
   // Removes the previously added TextBox from the form.
   void removeControl_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Loop through all controls in the form's control collection.
      IEnumerator^ myEnum = this->Controls->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         Control^ tempCtrl = safe_cast<Control^>(myEnum->Current);
         
         // Determine whether the control is textBox1,
         // and if it is, remove it.
         if ( tempCtrl->Name->Equals( "textBox1" ) )
         {
            this->Controls->Remove( tempCtrl );
         }
      }
   }

// This example demonstrates the use of the ControlAdded and
// ControlRemoved events. This example assumes that two Button controls
// are added to the form and connected to the addControl_Click and
// removeControl_Click event-handler methods.
private void Form1_Load(Object sender, System.EventArgs e)
{
    // Connect the ControlRemoved and ControlAdded event handlers
    // to the event-handler methods.
    // ControlRemoved and ControlAdded are not available at design time.
    this.add_ControlRemoved(new System.Windows.Forms.
        ControlEventHandler(this.Control_Removed));
    this.add_ControlAdded(new System.Windows.Forms.
        ControlEventHandler(this.Control_Added));
} //Form1_Load

private void Control_Added(Object sender, System.Windows.Forms.
    ControlEventArgs e)
{
    MessageBox.Show("The control named " + e.get_Control().get_Name() 
        + " has been added to the form.");
} //Control_Added

private void Control_Removed(Object sender, System.Windows.Forms.
    ControlEventArgs e)
{
    MessageBox.Show("The control named " + e.get_Control().get_Name() 
        + " has been removed from the form.");
} //Control_Removed

// Click event handler for a Button control. Adds a TextBox to the form.
private void addControl_Click(Object sender, System.EventArgs e)
{
    // Create a new TextBox control and add it to the form.
    TextBox textBox1 = new TextBox();
    textBox1.set_Size(new Size(100, 10));
    textBox1.set_Location(new Point(10, 10));

    // Name the control in order to remove it later. 
    // The name must be specified
    // if a control is added at run time.
    textBox1.set_Name("textBox1");

    // Add the control to the form's control collection.
    this.get_Controls().Add(textBox1);
} //addControl_Click

// Click event handler for a Button control.
// Removes the previously added TextBox from the form.
private void removeControl_Click(Object sender, System.EventArgs e)
{
    // Loop through all controls in the form's control collection.
    for (int iCtr = 0; iCtr < this.get_Controls().get_Count(); iCtr++) {
        Control tempCtrl = this.get_Controls().get_Item(iCtr);
        
        // Determine whether the control is textBox1,
        // and if it is, remove it.
        if (tempCtrl.get_Name().Equals("textBox1")) {
            this.get_Controls().Remove(tempCtrl);
        }
    }
} //removeControl_Click

Plattformen

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Freigeben über

Control.OnControlAdded-Methode

Syntax

Parameter

Hinweise

Beispiel

Plattformen

Versionsinformationen

.NET Framework

Siehe auch

Referenz

Zusätzliche Ressourcen