Gets or sets the active control on the container control.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
The property activates or retrieves the active control on the container control.
In order to receive a valid value from this property, the object that calls it must either contain or be contained in the control it is calling. If one form tries to call another form's properties, it will receive an undefined value. In this case, you need to define your own communication mechanism between the forms to pass this data.
The following code example inherits from the ScrollableControl class and implements the IContainerControl interface. Implementation is added to the ActiveControl property and the ActivateControl method.
Imports System Imports System.Windows.Forms Imports System.Drawing Public Class MyContainerControl Inherits ScrollableControl Implements IContainerControl Private myActiveControl As Control Public Sub New() ' Make the container control Blue so it can be distinguished on the form. Me.BackColor = Color.Blue ' Make the container scrollable. Me.AutoScroll = True End Sub ' Add implementation to the IContainerControl.ActiveControl property. Public Property ActiveControl() As Control Implements IContainerControl.ActiveControl Get Return Me.myActiveControl End Get Set ' Make sure the control is a member of the ControlCollection. If Me.Controls.Contains(value) Then Me.myActiveControl = value End If End Set End Property ' Add implementation to the IContainerControl.ActivateControl(Control) method. public Function ActivateControl(active As Control) As Boolean Implements IContainerControl.ActivateControl If Me.Controls.Contains(active) Then ' Select the control and scroll the control into view if needed. active.Select() Me.ScrollControlIntoView(active) Me.myActiveControl = active Return True End If Return False End Function End Class