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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)

[BrowsableAttribute(false)]
public:
virtual property Control^ ActiveControl {
	Control^ get () sealed;
	void set (Control^ value) sealed;
}

Property Value

Type: System.Windows.Forms::Control
The Control that is currently active on the ContainerControl.

Implements

IContainerControl::ActiveControl

ExceptionCondition
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;
   }
};

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
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