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ContainerControl.ActiveControl Property

Gets or sets the active control on the container control.

[Visual Basic]
Public Overridable Property ActiveControl As Control  Implements _
   IContainerControl.ActiveControl
[C#]
public virtual Control ActiveControl {get; set;}
[C++]
public: __property virtual Control* get_ActiveControl();
public: __property virtual void set_ActiveControl(Control*);
[JScript]
public function get ActiveControl() : Control;
public function set ActiveControl(Control);

Property Value

The Control that is currently active on the ContainerControl.

Implements

IContainerControl.ActiveControl

Exceptions

Exception Type Condition
ArgumentException The Control assigned could not be activated.

Remarks

This property activates or retrieves the active control on the container control.

Example

[Visual Basic, C#, C++] The following example inherits from the ScrollableControl class and implements the IContainerControl interface. Implementation is added to the ActiveControl property and the ActivateControl method.

[Visual Basic] 
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  

[C#] 
using System;
using System.Windows.Forms;
using System.Drawing;

    public class MyContainer : ScrollableControl, IContainerControl
    {
        private Control activeControl;
        public MyContainer() 
        {
            // Make the container control Blue so it can be distinguished on the form.
            this.BackColor = Color.Blue;
            
            // Make the container scrollable.
            this.AutoScroll = true;
        }

        // Add implementation to the IContainerControl.ActiveControl property.
        public Control ActiveControl
        {
            get
            {
                return activeControl;
            }

            set
            {
                // Make sure the control is a member of the ControlCollection.
                if(this.Controls.Contains(value))
                {
                    activeControl = value;
                }
            }
        }

        // Add implementations to the IContainerControl.ActivateControl(Control) method.
        public bool ActivateControl(Control active)
        {
            if(this.Controls.Contains(active))
            {
                // Select the control and scroll the control into view if needed.
                active.Select();
                this.ScrollControlIntoView(active);
                this.activeControl = active;
                return true;
            }
            return false;
        }
    }

[C++] 

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

    public __gc class MyContainer : public ScrollableControl, public IContainerControl {
    private:
        Control*  activeControl;

    public:
        MyContainer() {
            // Make the container control Blue so it can be distinguished on the form.
            this->BackColor = Color::Blue;

            // Make the container scrollable.
            this->AutoScroll = true;
        }

        // Add implementation to the IContainerControl.ActiveControl property.
        __property Control* get_ActiveControl() {
            return activeControl;    
        }

        __property void set_ActiveControl(Control* value) {
            // Make sure the control is a member of the ControlCollection.
            if (this->Controls->Contains(value)) {
                activeControl = value;
            }    
        }

        // Add implementations to the IContainerControl.ActivateControl(Control) method.
        bool ActivateControl(Control* active) {
            if (this->Controls->Contains(active)) {
                // Select the control and scroll the control into view if needed.
                active->Select();
                this->ScrollControlIntoView(active);
                this->activeControl = active;
                return true;
            }
            return false;
        }
    };

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

ContainerControl Class | ContainerControl Members | System.Windows.Forms Namespace | ScrollableControl | Control

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