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IComponentDiscoveryService interface

 

Date de publication : novembre 2016

Active l’énumération de composants au moment du design.

Espace de noms:   System.ComponentModel.Design
Assembly:  System (dans System.dll)

public interface IComponentDiscoveryService

NomDescription
System_CAPS_pubmethodGetComponentTypes(IDesignerHost, Type)

Obtient la liste des types de composants disponibles.

L’implémentation par défaut de le IComponentDiscoveryService interface permet l’énumération au moment du design des composants dans la boîte à outils.

Vous pouvez fournir une implémentation personnalisée qui énumère d’autres types disponibles au moment du design. Par exemple, votre implémentation peut énumérer les composants qui sont présents dans un concepteur particulier.

L’exemple de code suivant montre comment utiliser IComponentDiscoveryService pour rechercher tous les types qui dérivent de la ScrollableControl type.

// This class defines the smart tags that appear on the control
// that is being designed.
internal class DemoActionList :
      System.ComponentModel.Design.DesignerActionList
{
    // Cache a reference to the designer host.
    private IDesignerHost host = null;

    // Cache a reference to the control.
    private DemoControl relatedControl = null;

    // Cache a reference to the designer.
    private DemoControlDesigner relatedDesigner = null;

    //The constructor associates the control 
    //with the smart tag list.
    public DemoActionList(IComponent component)
        : base(component)
    {
        this.relatedControl = component as DemoControl;

        this.host =
            this.Component.Site.GetService(typeof(IDesignerHost))
            as IDesignerHost;

        IDesigner dcd = host.GetDesigner(this.Component);
        this.relatedDesigner = dcd as DemoControlDesigner;
    }

    // This method creates and populates the 
    // DesignerActionItemCollection which is used to 
    // display smart tag items.
    public override DesignerActionItemCollection GetSortedActionItems()
    {
        DesignerActionItemCollection items =
            new DesignerActionItemCollection();

        // If the Timer component has not been created, show the
        // "Create Timer" DesignerAction item.
        //
        // If the Timer component exists, show the timer-related
        // options.

        if (this.relatedDesigner.createdTimer == null)
        {
            items.Add(new DesignerActionMethodItem(
                this,
                "CreateTimer",
                "Create Timer",
                true));
        }
        else
        {   
            items.Add(new DesignerActionMethodItem(
                this,
                "ShowEventHandlerCode",
                "Show Event Handler Code",
                true));

            items.Add(new DesignerActionMethodItem(
                this,
                "RemoveTimer",
                "Remove Timer",
                true));
        }

        items.Add(new DesignerActionMethodItem(
           this,
           "GetExtenderProviders",
           "Get Extender Providers",
           true));

        items.Add(new DesignerActionMethodItem(
          this,
          "GetDemoControlReferences",
          "Get DemoControl References",
          true));

        items.Add(new DesignerActionMethodItem(
          this,
          "GetPathOfAssembly",
          "Get Path of Executing Assembly",
          true));

        items.Add(new DesignerActionMethodItem(
          this,
          "GetComponentTypes",
          "Get ScrollableControl Types",
          true));

        items.Add(new DesignerActionMethodItem(
            this,
            "GetToolboxCategories",
            "Get Toolbox Categories",
            true));

        items.Add(new DesignerActionMethodItem(
            this,
            "SetBackColor",
            "Set Back Color",
            true));

        return items;
    }

    // This method creates a Timer component using the 
    // IDesignerHost.CreateComponent method. It also 
    // creates an event handler for the Timer component's
    // tick event.
    private void CreateTimer()
    {
        if (this.host != null)
        {
            if (this.relatedDesigner.createdTimer == null)
            {
                // Create and configure the Timer object.
                this.relatedDesigner.createdTimer =
                    this.host.CreateComponent(typeof(Timer)) as Timer;
                Timer t = this.relatedDesigner.createdTimer;
                t.Interval = 1000;
                t.Enabled = true;

                EventDescriptorCollection eventColl =
                    TypeDescriptor.GetEvents(t, new Attribute[0]);

                if (eventColl != null)
                {
                    EventDescriptor ed =
                        eventColl["Tick"] as EventDescriptor;
                    if (ed != null)
                    {
                        PropertyDescriptor epd =
                            this.relatedDesigner.eventBindingService.GetEventProperty(ed);

                        epd.SetValue(t, "timer_Tick");
                    }
                }

	this.relatedDesigner.actionUiService.Refresh(this.relatedControl);
            }
        }
    }

    // This method uses the IEventBindingService.ShowCode
    // method to start the Code Editor. It places the caret
    // in the timer_tick method created by the CreateTimer method.
    private void ShowEventHandlerCode()
    {
        Timer t = this.relatedDesigner.createdTimer;

        if (t != null)
        {
            EventDescriptorCollection eventColl =
                TypeDescriptor.GetEvents(t, new Attribute[0]);
            if (eventColl != null)
            {
                EventDescriptor ed =
                    eventColl["Tick"] as EventDescriptor;
                if (ed != null)
                {
                    this.relatedDesigner.eventBindingService.ShowCode(t, ed);
                }
            }
        }
    }

    // This method uses the IDesignerHost.DestroyComponent method
    // to remove the Timer component from the design environment.
    private void RemoveTimer()
    {
        if (this.host != null)
        {
            if (this.relatedDesigner.createdTimer != null)
            {
                this.host.DestroyComponent(
                    this.relatedDesigner.createdTimer);

                this.relatedDesigner.createdTimer = null;

	this.relatedDesigner.actionUiService.Refresh(
                    this.relatedControl);
            }
        }
    }

    // This method uses IExtenderListService.GetExtenderProviders
    // to enumerate all the extender providers and display them 
    // in a MessageBox.
    private void GetExtenderProviders()
    {
        if (this.relatedDesigner.listService != null)
        {
            StringBuilder sb = new StringBuilder();

            IExtenderProvider[] providers =
                this.relatedDesigner.listService.GetExtenderProviders();

            for (int i = 0; i < providers.Length; i++)
            {
                sb.Append(providers[i].ToString());
                sb.Append("\r\n");
            }

            MessageBox.Show(
                sb.ToString(), 
                "Extender Providers");
        }
    }

    // This method uses the IReferenceService.GetReferences method
    // to enumerate all the instances of DemoControl on the 
    // design surface.
    private void GetDemoControlReferences()
    {
        if (this.relatedDesigner.referenceService != null)
        {
            StringBuilder sb = new StringBuilder();

            object[] refs = this.relatedDesigner.referenceService.GetReferences(typeof(DemoControl));

            for (int i = 0; i < refs.Length; i++)
            {
                sb.Append(refs[i].ToString());
                sb.Append("\r\n");
            }

            MessageBox.Show(
                sb.ToString(), 
                "DemoControl References");
        }
    }


    // This method uses the ITypeResolutionService.GetPathOfAssembly
    // method to display the path of the executing assembly.
    private void GetPathOfAssembly()
    {
        if (this.relatedDesigner.typeResService != null)
        {
            System.Reflection.AssemblyName name =
                System.Reflection.Assembly.GetExecutingAssembly().GetName();

            MessageBox.Show(
                this.relatedDesigner.typeResService.GetPathOfAssembly(name),
                "Path of executing assembly");
        }
    }

    // This method uses the IComponentDiscoveryService.GetComponentTypes 
    // method to find all the types that derive from 
    // ScrollableControl.
    private void GetComponentTypes()
    {
        if (this.relatedDesigner.componentDiscoveryService != null)
        {
            ICollection components = this.relatedDesigner.componentDiscoveryService.GetComponentTypes(host, typeof(ScrollableControl));

            if (components != null)
            {
                if (components.Count > 0)
                {
                    StringBuilder sb = new StringBuilder();

                    IEnumerator e = components.GetEnumerator();

                    while (e.MoveNext())
                    {
                        sb.Append(e.Current.ToString());
                        sb.Append("\r\n");

                    }

                    MessageBox.Show(
                        sb.ToString(), 
                        "Controls derived from ScrollableControl");
                }
            }
        }
    }

    // This method uses the IToolboxService.CategoryNames
    // method to enumerate all the categories that appear
    // in the Toolbox.
    private void GetToolboxCategories()
    {
        if (this.relatedDesigner.toolboxService != null)
        {
            StringBuilder sb = new StringBuilder();

            CategoryNameCollection names = this.relatedDesigner.toolboxService.CategoryNames;

            foreach (string name in names)
            {
                sb.Append(name.ToString());
                sb.Append("\r\n");
            }

            MessageBox.Show(sb.ToString(), "Toolbox Categories");
        }
    }

    // This method sets the shadowed BackColor property on the 
    // designer. This is the value that is serialized by the 
    // design environment.
    private void SetBackColor()
    {
        ColorDialog d = new ColorDialog();
        if (d.ShowDialog() == DialogResult.OK)
        {
            this.relatedDesigner.BackColor = d.Color;
        }
    }
}

.NET Framework
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