Control.OnControlAdded Method (ControlEventArgs)

 

Raises the ControlAdded event.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

Protected Overridable Sub OnControlAdded (
	e As ControlEventArgs
)

Parameters

e
Type: System.Windows.Forms.ControlEventArgs

A ControlEventArgs that contains the event data.

Called when a child control is added to the control.

Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.

The OnControlAdded method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors:

When overriding OnControlAdded in a derived class, be sure to call the base class's OnControlAdded method so that registered delegates receive the event.

The following code example uses ControlAdded to add a control to a form and displays the name of the added control in a MessageBox.

' 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

.NET Framework
Available since 1.1
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