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IDesignerEventService Interface

Provides event notifications when root designers are added and removed, when a selected component changes, and when the current root designer changes.

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

public interface class IDesignerEventService

The IDesignerEventService type exposes the following members.

  NameDescription
Public propertyActiveDesignerGets the root designer for the currently active document.
Public propertyDesignersGets a collection of root designers for design documents that are currently active in the development environment.
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  NameDescription
Public eventActiveDesignerChangedOccurs when the current root designer changes.
Public eventDesignerCreatedOccurs when a root designer is created.
Public eventDesignerDisposedOccurs when a root designer for a document is disposed.
Public eventSelectionChangedOccurs when the current design-view selection changes.
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IDesignerEventService provides notification when a new root designer is created, changed, or disposed. A root designer provides design time support for the base component of a document in designer view. The SelectionChanged event provides notification when the current component selection has changed.

This example demonstrates a designer that uses the IDesignerEventService to display event notifications on a control. To use this example, compile the code to a class library. Add a reference to the library to a new Windows Forms project, and add the control within the library to the Toolbox. Add an instance of the DesignerMonitor control to a form in design mode. Right-click the control and click the Start monitoring command to display notifications of events raised by the IDesignerEventService.

#using <system.dll>
#using <system.design.dll>
#using <system.windows.forms.dll>
#using <system.drawing.dll>

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

namespace DesignerEventServiceExample
{
   ref class DesignerMonitorDesigner;

   // DesignerMonitor provides a display for designer event notifications.

   [Designer(DesignerEventServiceExample::DesignerMonitorDesigner::typeid)]
   public ref class DesignerMonitor: public UserControl
   {
   public:

      // List to contain strings that describe designer events.
      ArrayList^ updates;
      bool monitoring_events;
      DesignerMonitor()
      {
         monitoring_events = false;
         updates = gcnew ArrayList;
         this->BackColor = Color::White;
         this->Size = System::Drawing::Size( 450, 300 );
      }

   protected:

      // Display the message for the current mode, and any event messages if event monitoring is active. 
      virtual void OnPaint( PaintEventArgs^ e ) override
      {
         e->Graphics->DrawString( "IDesignerEventService DesignerMonitor Control", gcnew System::Drawing::Font( FontFamily::GenericMonospace,10 ), gcnew SolidBrush( Color::Blue ), 5, 4 );
         int yoffset = 10;
         if (  !monitoring_events )
         {
            yoffset += 10;
            e->Graphics->DrawString( "Currently not monitoring designer events.", gcnew System::Drawing::Font( FontFamily::GenericMonospace,10 ), gcnew SolidBrush( Color::Black ), 5.f, yoffset + 10.f );
            e->Graphics->DrawString( "Use the shortcut menu commands", gcnew System::Drawing::Font( FontFamily::GenericMonospace,10 ), gcnew SolidBrush( Color::Black ), 5.f, yoffset + 30.f );
            e->Graphics->DrawString( "provided by an associated DesignerMonitorDesigner", gcnew System::Drawing::Font( FontFamily::GenericMonospace,10 ), gcnew SolidBrush( Color::Black ), 5.f, yoffset + 40.f );
            e->Graphics->DrawString( "to start or stop monitoring.", gcnew System::Drawing::Font( FontFamily::GenericMonospace,10 ), gcnew SolidBrush( Color::Black ), 5.f, yoffset + 50.f );
         }
         else
         {
            e->Graphics->DrawString( "Currently monitoring designer events.", gcnew System::Drawing::Font( FontFamily::GenericMonospace,10 ), gcnew SolidBrush( Color::DarkBlue ), 5.f, yoffset + 10.f );
            e->Graphics->DrawString( "Designer created, changed and disposed events:", gcnew System::Drawing::Font( FontFamily::GenericMonospace,9 ), gcnew SolidBrush( Color::Brown ), 5.f, yoffset + 35.f );
            for ( int i = 0; i < updates->Count; i++ )
            {
               e->Graphics->DrawString( static_cast<String^>(updates[ i ]), gcnew System::Drawing::Font( FontFamily::GenericMonospace,8 ), gcnew SolidBrush( Color::Black ), 5.f, yoffset + 55.f + (10 * i) );
               yoffset += 10;
            }
         }
      }
   };

   // DesignerMonitorDesigner uses the IDesignerEventService to send event information 
   // to an associated DesignerMonitor control's updates collection. 
   public ref class DesignerMonitorDesigner: public ControlDesigner
   {
   private:
      DesignerMonitor^ dm;
      DesignerVerbCollection^ dvc;
      int eventcount;
      void StopMonitoring( Object^ /*sender*/, EventArgs^ /*e*/ )
      {
         IDesignerEventService^ des = dynamic_cast<IDesignerEventService^>(this->Control->Site->GetService( IDesignerEventService::typeid ));
         if ( des != nullptr )
         {
            // Remove event handlers for event notification methods.
            des->DesignerCreated -= gcnew DesignerEventHandler( this, &DesignerMonitorDesigner::DesignerCreated );
            des->DesignerDisposed -= gcnew DesignerEventHandler( this, &DesignerMonitorDesigner::DesignerDisposed );
            des->ActiveDesignerChanged -= gcnew ActiveDesignerEventHandler( this, &DesignerMonitorDesigner::DesignerChanged );
            des->SelectionChanged -= gcnew EventHandler( this, &DesignerMonitorDesigner::SelectionChanged );
            dm->monitoring_events = false;

            // Rebuild menu with "Start monitoring" command.
            array<DesignerVerb^>^myArray = {gcnew DesignerVerb( "Start monitoring",gcnew EventHandler( this, &DesignerMonitorDesigner::StartMonitoring ) )};
            dvc = gcnew DesignerVerbCollection( myArray );
            dm->Refresh();
         }
      }

      void StartMonitoring( Object^ /*sender*/, EventArgs^ /*e*/ )
      {
         IDesignerEventService^ des = dynamic_cast<IDesignerEventService^>(this->Control->Site->GetService( IDesignerEventService::typeid ));
         if ( des != nullptr )
         {
            // Add event handlers for event notification methods.
            des->DesignerCreated += gcnew DesignerEventHandler( this, &DesignerMonitorDesigner::DesignerCreated );
            des->DesignerDisposed += gcnew DesignerEventHandler( this, &DesignerMonitorDesigner::DesignerDisposed );
            des->ActiveDesignerChanged += gcnew ActiveDesignerEventHandler( this, &DesignerMonitorDesigner::DesignerChanged );
            des->SelectionChanged += gcnew EventHandler( this, &DesignerMonitorDesigner::SelectionChanged );
            dm->monitoring_events = false;

            // Rebuild menu with "Stop monitoring" command.
            array<DesignerVerb^>^myArray = {gcnew DesignerVerb( "Stop monitoring",gcnew EventHandler( this, &DesignerMonitorDesigner::StopMonitoring ) )};
            dvc = gcnew DesignerVerbCollection( myArray );
            dm->Refresh();
         }
      }

      void DesignerCreated( Object^ /*sender*/, DesignerEventArgs^ e )
      {
         UpdateStatus( "Designer for " + e->Designer->RootComponent->Site->Name + " was created." );
      }

      void DesignerDisposed( Object^ /*sender*/, DesignerEventArgs^ e )
      {
         UpdateStatus( "Designer for " + e->Designer->RootComponent->Site->Name + " was disposed." );
      }

      void DesignerChanged( Object^ /*sender*/, ActiveDesignerEventArgs^ e )
      {
         UpdateStatus( "Active designer moved from " + e->OldDesigner->RootComponent->Site->Name + " to " + e->NewDesigner->RootComponent->Site->Name + "." );
      }

      void SelectionChanged( Object^ /*sender*/, EventArgs^ /*e*/ )
      {
         UpdateStatus("A component selection was changed.");
      }

      // Update message buffer on DesignerMonitor control. 
      void UpdateStatus( String^ newmsg )
      {
         if ( dm->updates->Count > 10 )
                  dm->updates->RemoveAt( 10 );

         dm->updates->Insert( 0, "Event #" + eventcount.ToString() + ": " + newmsg );
         eventcount++;
         dm->Refresh();
      }
   };
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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