System.ComponentModel.Desig ...


.NET Framework Class Library
ComponentDesigner Class

Extends the design mode behavior of a component.

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

Visual Basic (Declaration)
Public Class ComponentDesigner _
    Implements ITreeDesigner, IDesigner, IDisposable, IDesignerFilter,  _
    IComponentInitializer
Visual Basic (Usage)
Dim instance As ComponentDesigner
C#
public class ComponentDesigner : ITreeDesigner, 
    IDesigner, IDisposable, IDesignerFilter, IComponentInitializer
Visual C++
public ref class ComponentDesigner : ITreeDesigner, 
    IDesigner, IDisposable, IDesignerFilter, IComponentInitializer
JScript
public class ComponentDesigner implements ITreeDesigner, IDesigner, IDisposable, IDesignerFilter, IComponentInitializer
Remarks

The ComponentDesigner base designer class provides a simple designer that can extend the behavior of an associated component in design mode.

ComponentDesigner provides an empty IDesignerFilter interface implementation, whose methods can be overridden to adjust the attributes, properties and events of the associated component at design time.

You can associate a designer with a type using a DesignerAttribute. For an overview of customizing design-time behavior, see Extending Design-Time Support.

The ComponentDesigner class implements a special behavior for the property descriptors of inherited components. An internal type named InheritedPropertyDescriptor is used by the default ComponentDesigner implementation to stand in for properties that are inherited from a base class. There are two cases in which these property descriptors are added.

  1. To the root object itself, which is returned by the IDesignerHost..::.RootComponent property, because you are inheriting from its base class.

  2. To fields found in the base class of the root object. Public and protected fields from the base class are added to the designer so that they can be manipulated by the user.

The InheritedPropertyDescriptor class modifies the default value of a property, so that the default value is the current value at object instantiation. This is because the property is inherited from another instance. The designer defines resetting the property value as setting it to the value that was set by the inherited class. This value may differ from the default value stored in metadata.

Examples

The following code example provides an example ComponentDesigner implementation and an example component associated with the designer. The designer implements an override of the Initialize method that calls the base Initialize method, an override of the DoDefaultAction method that displays a MessageBox when the component is double-clicked, and an override of the Verbs property accessor that supplies a custom DesignerVerb menu command to the shortcut menu for the component.

Visual Basic
Imports System
Imports System.Collections
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.Drawing
Imports System.Windows.Forms

Namespace ExampleComponent

    ' Provides an example component designer.
    Public Class ExampleComponentDesigner
        Inherits System.ComponentModel.Design.ComponentDesigner

        Public Sub New()
        End Sub 'New

        ' This method provides an opportunity to perform processing when a designer is initialized.
        ' The component parameter is the component that the designer is associated with.
        Public Overrides Sub Initialize(ByVal component As System.ComponentModel.IComponent)
            ' Always call the base Initialize method in an override of this method.
            MyBase.Initialize(component)
        End Sub 'Initialize

        ' This method is invoked when the associated component is double-clicked.
        Public Overrides Sub DoDefaultAction()
            MessageBox.Show("The event handler for the default action was invoked.")
        End Sub 'DoDefaultAction

        ' This method provides designer verbs.
        Public Overrides ReadOnly Property Verbs() As System.ComponentModel.Design.DesignerVerbCollection
            Get
                Return New DesignerVerbCollection(New DesignerVerb() {New DesignerVerb("Example Designer Verb Command", New EventHandler(AddressOf Me.onVerb))})
            End Get
        End Property

        ' Event handling method for the example designer verb
        Private Sub onVerb(ByVal sender As Object, ByVal e As EventArgs)
            MessageBox.Show("The event handler for the Example Designer Verb Command was invoked.")
        End Sub 'onVerb
    End Class 'ExampleComponentDesigner

    ' Provides an example component associated with the example component designer.
    <DesignerAttribute(GetType(ExampleComponentDesigner), GetType(IDesigner))> _
     Public Class ExampleComponent
        Inherits System.ComponentModel.Component

        Public Sub New()
        End Sub 'New
    End Class 'ExampleComponent

End Namespace 'ExampleComponent
C#
using System;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Windows.Forms;

namespace ExampleComponent
{    
    // Provides an example component designer.
    public class ExampleComponentDesigner : System.ComponentModel.Design.ComponentDesigner
    {
        public ExampleComponentDesigner()
        {
        }

        // This method provides an opportunity to perform processing when a designer is initialized.
        // The component parameter is the component that the designer is associated with.
        public override void Initialize(System.ComponentModel.IComponent component)
        {
            // Always call the base Initialize method in an override of this method.
            base.Initialize(component);
        }

        // This method is invoked when the associated component is double-clicked.
        public override void DoDefaultAction()
        {
            MessageBox.Show("The event handler for the default action was invoked.");
        }

        // This method provides designer verbs.
        public override System.ComponentModel.Design.DesignerVerbCollection Verbs
        {
            get
            {
                return new DesignerVerbCollection( new DesignerVerb[] { new DesignerVerb("Example Designer Verb Command", new EventHandler(this.onVerb)) } );
            }
        }

        // Event handling method for the example designer verb
        private void onVerb(object sender, EventArgs e)
        {
            MessageBox.Show("The event handler for the Example Designer Verb Command was invoked.");
        }
    }

    // Provides an example component associated with the example component designer.
    [DesignerAttribute(typeof(ExampleComponentDesigner), typeof(IDesigner))]
    public class ExampleComponent : System.ComponentModel.Component
    {        
        public ExampleComponent()
        {
        }
    }
}
Visual C++
#using <System.dll>
#using <System.Design.dll>
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>

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

// Provides an example component designer.
ref class ExampleComponentDesigner: public ComponentDesigner
{
public:
   ExampleComponentDesigner()
   {
   }

   // This method provides an opportunity to perform processing when a designer is initialized.
   // The component parameter is the component that the designer is associated with.
   virtual void Initialize( IComponent^ component ) override
   {
      // Always call the base Initialize method in an of this method.
      ComponentDesigner::Initialize( component );
   }

   // This method is invoked when the associated component is double-clicked.
   virtual void DoDefaultAction() override
   {
      MessageBox::Show( "The event handler for the default action was invoked." );
   }

   // This method provides designer verbs.
   property DesignerVerbCollection^ Verbs 
   {
      virtual DesignerVerbCollection^ get() override
      {
         array<DesignerVerb^>^ newDesignerVerbs = {gcnew DesignerVerb( "Example Designer Verb Command", gcnew EventHandler( this, &ExampleComponentDesigner::onVerb ) )};
         return gcnew DesignerVerbCollection( newDesignerVerbs );
      }
   }

private:
   // Event handling method for the example designer verb
   void onVerb( Object^ sender, EventArgs^ e )
   {
      MessageBox::Show( "The event handler for the Example Designer Verb Command was invoked." );
   }
};

// Provides an example component associated with the example component designer.

[DesignerAttribute(ExampleComponentDesigner::typeid, IDesigner::typeid)]
ref class ExampleComponent: public Component
{
public:
   ExampleComponent(){}
};
Inheritance Hierarchy

System..::.Object
  System.ComponentModel.Design..::.ComponentDesigner
    System.Diagnostics.Design..::.ProcessDesigner
    System.Diagnostics.Design..::.ProcessModuleDesigner
    System.Diagnostics.Design..::.ProcessThreadDesigner
    System.Messaging.Design..::.MessageDesigner
    System.ServiceProcess.Design..::.ServiceControllerDesigner
    System.Web.UI.Design..::.HtmlControlDesigner
    System.Windows.Forms.Design..::.ComponentDocumentDesigner
    System.Windows.Forms.Design..::.ControlDesigner
Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Platforms

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.
Version Information

.NET Framework

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

Reference

Other Resources

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