Control.OnControlRemoved 方法

项目
08/17/2007

**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）

语法

声明
Protected Overridable Sub OnControlRemoved ( _
    e As ControlEventArgs _
)
用法
Dim e As ControlEventArgs

Me.OnControlRemoved(e)

protected virtual void OnControlRemoved (
    ControlEventArgs e
)

protected:
virtual void OnControlRemoved (
    ControlEventArgs^ e
)

protected void OnControlRemoved (
    ControlEventArgs e
)

protected function OnControlRemoved (
    e : ControlEventArgs
)

参数

e
包含事件数据的 ControlEventArgs。

备注

从此控件中移除子控件时调用。

引发事件时会通过委托调用事件处理程序。有关更多信息，请参见引发事件。

OnControlRemoved 方法还允许派生类对事件进行处理而不必附加委托。这是在派生类中处理事件的首选技术。

给继承者的说明 在派生类中重写 OnControlRemoved 时，一定要调用基类的 OnControlRemoved 方法，以便已注册的委托对事件进行接收。

示例

下面的代码示例使用 ControlRemoved 从窗体中移除控件，并在 MessageBox 中显示所移除的控件的名称。

' 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

平台

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

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

通过

Control.OnControlRemoved 方法

语法

参数

备注

示例

平台

版本信息

.NET Framework

请参见

参考

其他资源