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ContainerControl.ActiveControl Property

Gets or sets the active control on the container control.

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

public:
virtual property Control^ ActiveControl {
	Control^ get () sealed;
	void set (Control^ value) sealed;
}
/** @property */
public final Control get_ActiveControl ()

/** @property */
public final void set_ActiveControl (Control value)

public final function get ActiveControl () : Control

public final function set ActiveControl (value : Control)

Property Value

The Control that is currently active on the ContainerControl.

Exception typeCondition

ArgumentException

The Control assigned could not be activated.

The ActiveControl 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 ActiveControl 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.

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

public ref 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;
   }

   property Control^ ActiveControl 
   {
      // Add implementation to the IContainerControl.ActiveControl property.
      virtual Control^ get()
      {
         return activeControl;
      }

      virtual void set( 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.
   virtual 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;
   }
};

import System.*;
import System.Windows.Forms.*;
import System.Drawing.*;

public class MyContainer extends ScrollableControl implements IContainerControl
{
    private Control activeControl;

    public MyContainer()
    {
        // Make the container control Blue so it can be 
        // distinguished on the form.
        this.set_BackColor(Color.get_Blue());

        // Make the container scrollable.
        this.set_AutoScroll(true);
    } //MyContainer

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

    /** @property 
     */
    public void set_ActiveControl(Control value)
    {
        // Make sure the control is a member of the ControlCollection.
        if (this.get_Controls().Contains(value)) {
            activeControl = value;
        }
    } //set_ActiveControl

    // Add implementations to the IContainerControl.
    // ActivateControl(Control) method.
    public boolean ActivateControl(Control active)
    {
        if (this.get_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;
    } //ActivateControl
} //MyContainer

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

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0
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