IRootDesigner Interface


Provides support for root-level designer view technologies.

Namespace:   System.ComponentModel.Design
Assembly:  System (in System.dll)

public interface class IRootDesigner : IDesigner, IDisposable


Gets the base component that this designer is designing.(Inherited from IDesigner.)


Gets the set of technologies that this designer can support for its display.


Gets a collection of the design-time verbs supported by the designer.(Inherited from IDesigner.)


Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.(Inherited from IDisposable.)


Performs the default action for this designer.(Inherited from IDesigner.)


Gets a view object for the specified view technology.


Initializes the designer with the specified component.(Inherited from IDesigner.)

A root designer is the designer that is in the top position, or root, of the current design-time document object hierarchy. A root designer must implement the IRootDesigner interface. A root designer typically manages the background view in designer view mode, and usually displays the controls within the base container of the current design time project.

The following code example demonstrates a IRootDesigner implementation associated with a sample user control. This IRootDesigner implementation displays a control for the background view in designer view by overriding the GetView method. You need to add a reference to the System.Design assembly to compile the example.

To use this example, add the source code to a project and show the RootViewSampleComponent in designer view to display the custom root designer view.

#using <System.Windows.Forms.dll>
#using <System.Drawing.dll>
#using <System.Design.dll>
#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::ComponentModel;
using namespace System::ComponentModel::Design;
using namespace System::Diagnostics;
using namespace System::Drawing;
using namespace System::Windows::Forms;
using namespace System::Windows::Forms::Design;

namespace SampleRootDesigner
   ref class SampleRootDesigner;

   // This sample demonstrates how to provide the root designer view, or
   // design mode background view, by overriding IRootDesigner.GetView().
   // The following attribute associates the SampleRootDesigner designer
   // with the SampleComponent component.

   public ref class RootDesignedComponent: public Component


   public ref class SampleRootDesigner: public ComponentDesigner, public IRootDesigner
      ref class RootDesignerView;

      // Member field of custom type RootDesignerView, a control that
      // will be shown in the Forms designer view. This member is
      // cached to reduce processing needed to recreate the
      // view control on each call to GetView().
      RootDesignerView^ m_view;

      // This method returns an instance of the view for this root
      // designer. The "view" is the user interface that is presented
      // in a document window for the user to manipulate.
      virtual Object^ GetView( ViewTechnology technology ) sealed = IRootDesigner::GetView
         if ( technology != ViewTechnology::WindowsForms )
            throw gcnew ArgumentException( "Not a supported view technology","technology" );

         if ( m_view == nullptr )

            // Some type of displayable Form or control is required
            // for a root designer that overrides GetView(). In this
            // example, a Control of type RootDesignerView is used.
            // Any class that inherits from Control will work.
            m_view = gcnew RootDesignerView( this );

         return m_view;

      // IRootDesigner.SupportedTechnologies is a required override for an
      // IRootDesigner. WindowsForms is the view technology used by this designer.
      property array<ViewTechnology>^ SupportedTechnologies 
		virtual array<ViewTechnology>^ get() 
			return gcnew array<ViewTechnology> {ViewTechnology::Default};


      // RootDesignerView is a simple control that will be displayed
      // in the designer window.
      ref class RootDesignerView: public Control
         SampleRootDesigner^ m_designer;

         RootDesignerView( SampleRootDesigner^ designer )
            m_designer = designer;
            BackColor = Color::Blue;
            Font = gcnew System::Drawing::Font( Font->FontFamily->Name,24.0f );

         virtual void OnPaint( PaintEventArgs^ pe ) override
            Control::OnPaint( pe );

            // Draws the name of the component in large letters.
            pe->Graphics->DrawString( m_designer->Component->Site->Name, Font, Brushes::Yellow, ClientRectangle );



   // This sample component inherits from RootDesignedComponent which
   // uses the SampleRootDesigner.
   public ref class RootViewSampleComponent: public RootDesignedComponent



.NET Framework
Available since 1.1
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