IReferenceService Interface

Provides an interface for obtaining references to objects within a project by name or type, obtaining the name of a specified object, and for locating the parent of a specified object within a designer project.

For a list of all members of this type, see IReferenceService Members.

[Visual Basic]
Public Interface IReferenceService
[C#]
public interface IReferenceService
[C++]
public __gc __interface IReferenceService
[JScript]
public interface IReferenceService

Remarks

The IReferenceService interface provides the following methods:

The GetReference method returns the component with the specified name, or a null reference (Nothing in Visual Basic) if no component with the specified name was found.
The GetName method returns the name associated with the specified component.
The GetComponent method returns the parent container of the specified component.
The GetReferences method returns an array of references to all project components, or all project components of an optionally specified type.

Example

[Visual Basic, C#] The following example control uses the GetReferences method of the IReferenceService interface to obtain a list of components in the current design mode project of the type of the currently selected component.

[Visual Basic] 
Imports System
Imports System.Collections
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.Drawing
Imports System.Data
Imports System.Windows.Forms

Namespace IReferenceServiceExample

    ' This control displays the name and type of the primary selection 
    ' component in design mode, if there is one,
    ' and uses the IReferenceService interface to display the names of 
    ' any components of the type of the primary selected component.    
    ' This control uses the IComponentChangeService to monitor for 
    ' selection changed events.    
    Public Class IReferenceServiceControl
        Inherits System.Windows.Forms.UserControl
        ' Indicates the name of the type of the selected component, or "None selected."
        Private selected_typename As String
        ' Indicates the name of the base type of the selected component, or "None selected."
        Private selected_basetypename As String
        ' Indicates the name of the selected component.
        Private selected_componentname As String
        ' Contains the names of components of the type of the selected 
        ' component in design mode.
        Private typeComponents() As String
        ' Contains the names of components of the base type of the selected component in design mode.
        Private basetypeComponents() As String
        ' Reference to the IComponentChangeService for the current component.
        Private selectionService As ISelectionService

        Public Sub New()
            ' Initializes the control properties.
            Me.BackColor = Color.White
            Me.SetStyle(ControlStyles.ResizeRedraw, True)
            Me.Name = "IReferenceServiceControl"
            Me.Size = New System.Drawing.Size(500, 250)
            ' Initializes the data properties.
            typeComponents = New String(0) {}
            basetypeComponents = New String(0) {}
            selected_typename = "None selected."
            selected_basetypename = "None selected."
            selected_componentname = "None selected."
            selectionService = Nothing
        End Sub

        ' Registers and unregisters design-mode services when 
        ' the component is sited and unsited.
        Public Overrides Property Site() As System.ComponentModel.ISite
            Get
                ' Returns the site for the control.
                Return MyBase.Site
            End Get
            Set(ByVal Value As System.ComponentModel.ISite)
                ' The site is set to null when a component is cut or 
                ' removed from a design-mode site.

                ' If an event handler has already been linked with 
                ' an ISelectionService, remove the handler.
                If Not (selectionService Is Nothing) Then
                    RemoveHandler selectionService.SelectionChanged, AddressOf Me.OnSelectionChanged
                End If

                ' Sites the control.
                MyBase.Site = Value

                ' Obtains an ISelectionService interface to register 
                ' the selection changed event handler with.
                selectionService = CType(Me.GetService(GetType(ISelectionService)), ISelectionService)
                If Not (selectionService Is Nothing) Then
                    AddHandler selectionService.SelectionChanged, AddressOf Me.OnSelectionChanged
                    ' Updates the display for the current selection, if any.
                    DisplayComponentsOfSelectedComponentType()
                End If
            End Set
        End Property

        ' Updates the display according to the primary selected component, 
        ' if any, and the names of design-mode components that the 
        ' IReferenceService returns references for when queried for 
        ' references to components of the primary selected component's 
        ' type and base type.
        Private Sub DisplayComponentsOfSelectedComponentType()
            ' If a component is selected...
            If Not (selectionService.PrimarySelection Is Nothing) Then
                ' Sets the selected type name and selected component name 
                ' to the type and name of the primary selected component.
                selected_typename = selectionService.PrimarySelection.GetType().FullName
                selected_basetypename = selectionService.PrimarySelection.GetType().BaseType.FullName
                selected_componentname = CType(selectionService.PrimarySelection, IComponent).Site.Name

                ' Obtain an IReferenceService and obtain references to 
                ' each component in the design-mode project.
                ' of the selected component's type and base type.
                Dim rs As IReferenceService = CType(Me.GetService(GetType(IReferenceService)), IReferenceService)
                If Not (rs Is Nothing) Then
                    ' Get references to design-mode components of the 
                    ' primary selected component's type.
                    Dim comps As Object() = CType(rs.GetReferences(selectionService.PrimarySelection.GetType()), Object())
                    typeComponents = New String(comps.Length) {}
                    Dim i As Integer
                    For i = 0 To comps.Length - 1
                        typeComponents(i) = CType(comps(i), IComponent).Site.Name
                    Next i
                    ' Get references to design-mode components with a base type 
                    ' of the primary selected component's base type.
                    comps = CType(rs.GetReferences(selectionService.PrimarySelection.GetType().BaseType), Object())
                    basetypeComponents = New String(comps.Length) {}               
                    For i = 0 To comps.Length - 1
                        basetypeComponents(i) = CType(comps(i), IComponent).Site.Name
                    Next i
                End If
            Else
                selected_typename = "None selected."
                selected_basetypename = "None selected."
                selected_componentname = "None selected."
                typeComponents = New String(0) {}
                basetypeComponents = New String(0) {}
            End If
            Me.Refresh()
        End Sub 'DisplayComponentsOfSelectedComponentType

        Private Sub OnSelectionChanged(ByVal sender As Object, ByVal e As EventArgs)
            DisplayComponentsOfSelectedComponentType()
        End Sub 'OnSelectionChanged

        Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
            e.Graphics.DrawString("IReferenceService Example Control", New Font(FontFamily.GenericMonospace, 9), New SolidBrush(Color.Blue), 5, 5)

            e.Graphics.DrawString("Primary Selected Component from IComponentChangeService:", New Font(FontFamily.GenericMonospace, 8), New SolidBrush(Color.Red), 5, 20)
            e.Graphics.DrawString("Name:      " + selected_componentname, New Font(FontFamily.GenericMonospace, 8), New SolidBrush(Color.Black), 10, 32)
            e.Graphics.DrawString("Type:      " + selected_typename, New Font(FontFamily.GenericMonospace, 8), New SolidBrush(Color.Black), 10, 44)
            e.Graphics.DrawString("Base Type: " + selected_basetypename, New Font(FontFamily.GenericMonospace, 8), New SolidBrush(Color.Black), 10, 56)
            e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 5, 77, Me.Width - 10, 77)

            e.Graphics.DrawString("Components of Type from IReferenceService:", New Font(FontFamily.GenericMonospace, 8), New SolidBrush(Color.Red), 5, 85)
            If selected_typename <> "None selected." Then
                Dim i As Integer
                For i = 0 To typeComponents.Length - 1
                    e.Graphics.DrawString(typeComponents(i), New Font(FontFamily.GenericMonospace, 8), New SolidBrush(Color.Black), 20, 97 + i * 12)
                Next i
            End If
            e.Graphics.DrawString("Components of Base Type from IReferenceService:", New Font(FontFamily.GenericMonospace, 8), New SolidBrush(Color.Red), 5, 109 + typeComponents.Length * 12)
            If selected_typename <> "None selected." Then
                Dim i As Integer
                For i = 0 To basetypeComponents.Length - 1
                    e.Graphics.DrawString(basetypeComponents(i), New Font(FontFamily.GenericMonospace, 8), New SolidBrush(Color.Black), 20, 121 + typeComponents.Length * 12 + i * 12)
                Next i
            End If
        End Sub 'OnPaint

    End Class 'IReferenceServiceControl
End Namespace 'IReferenceServiceExample

[C#] 
using System;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Data;
using System.Windows.Forms;

namespace IReferenceServiceExample
{
    // This control displays the name and type of the primary selection 
    // component in design mode, if there is one,
    // and uses the IReferenceService interface to display the names of 
    // any components of the type of the primary selected component.    
    // This control uses the IComponentChangeService to monitor for 
    // selection changed events.
    public class IReferenceServiceControl : System.Windows.Forms.UserControl
    {
            // Indicates the name of the type of the selected component, or "None selected.".
            private string selected_typename;
            // Indicates the name of the base type of the selected component, or "None selected."
            private string selected_basetypename;
            // Indicates the name of the selected component.
            private string selected_componentname;
            // Contains the names of components of the type of the selected 
            // component in design mode.
            private string[] typeComponents;
            // Contains the names of components of the base type of the selected component in design mode.
            private string[] basetypeComponents;
            // Reference to the IComponentChangeService for the current component.
            private ISelectionService selectionService;
        
            public IReferenceServiceControl()
            {
                // Initializes the control properties.
                this.BackColor = Color.White;
                this.SetStyle(ControlStyles.ResizeRedraw, true);
                this.Name = "IReferenceServiceControl";
                this.Size = new System.Drawing.Size(500, 250);                                    
                // Initializes the data properties.
                typeComponents = new string[0];
                basetypeComponents = new string[0];
                selected_typename = "None selected.";
                selected_basetypename = "None selected.";
                selected_componentname = "None selected.";
                selectionService = null;
            }

            // Registers and unregisters design-mode services when 
            // the component is sited and unsited.
            public override System.ComponentModel.ISite Site
            {
                get
                {
                    // Returns the site for the control.
                    return base.Site;
                }
                set
                {
                    // The site is set to null when a component is cut or 
                    // removed from a design-mode site.

                    // If an event handler has already been linked with 
                    // an ISelectionService, remove the handler.
                    if(selectionService != null)
                        selectionService.SelectionChanged -= new EventHandler(this.OnSelectionChanged);

                    // Sites the control.
                    base.Site = value;
                
                    // Obtains an ISelectionService interface to register 
                    // the selection changed event handler with.
                    selectionService = (ISelectionService)this.GetService(typeof(ISelectionService));
                    if( selectionService!= null )
                    {
                        selectionService.SelectionChanged += new EventHandler(this.OnSelectionChanged);
                        // Updates the display for the current selection, if any.
                        DisplayComponentsOfSelectedComponentType();
                    }
                }
            }

            // Updates the display according to the primary selected component, 
            // if any, and the names of design-mode components that the 
            // IReferenceService returns references for when queried for 
            // references to components of the primary selected component's 
            // type and base type.
            private void DisplayComponentsOfSelectedComponentType()
            {
                // If a component is selected...
                if( selectionService.PrimarySelection != null )
                {              
                    // Sets the selected type name and selected component name to the type and name of the primary selected component.
                    selected_typename = selectionService.PrimarySelection.GetType().FullName;
                    selected_basetypename = selectionService.PrimarySelection.GetType().BaseType.FullName;
                    selected_componentname = ((IComponent)selectionService.PrimarySelection).Site.Name;                

                    // Obtain an IReferenceService and obtain references to 
                    // each component in the design-mode project
                    // of the selected component's type and base type.
                    IReferenceService rs = (IReferenceService)this.GetService(typeof(IReferenceService));
                    if( rs != null )
                    {
                        // Get references to design-mode components of the 
                        // primary selected component's type.
                        object[] comps = (object[])rs.GetReferences( selectionService.PrimarySelection.GetType() );
                        typeComponents = new string[comps.Length];
                        for(int i=0; i<comps.Length; i++)
                            typeComponents[i] = ((IComponent)comps[i]).Site.Name;
   
                        // Get references to design-mode components with a base type 
                        // of the primary selected component's base type.
                        comps = (object[])rs.GetReferences( selectionService.PrimarySelection.GetType().BaseType );
                        basetypeComponents = new string[comps.Length];
                        for(int i=0; i<comps.Length; i++)
                            basetypeComponents[i] = ((IComponent)comps[i]).Site.Name;
                    }
                }
                else
                {
                    selected_typename = "None selected.";
                    selected_basetypename = "None selected.";
                    selected_componentname = "None selected.";
                    typeComponents = new string[0];
                    basetypeComponents = new string[0];
                }
                this.Refresh();
            }

            private void OnSelectionChanged(object sender, EventArgs e)
            {
                DisplayComponentsOfSelectedComponentType();
            }

            protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
            {
                e.Graphics.DrawString("IReferenceService Example Control", new Font(FontFamily.GenericMonospace, 9), new SolidBrush(Color.Blue), 5, 5);

                e.Graphics.DrawString("Primary Selected Component from IComponentChangeService:", new Font(FontFamily.GenericMonospace, 8), new SolidBrush(Color.Red), 5, 20);
                e.Graphics.DrawString("Name:      "+selected_componentname, new Font(FontFamily.GenericMonospace, 8), new SolidBrush(Color.Black), 10, 32);
                e.Graphics.DrawString("Type:      "+selected_typename, new Font(FontFamily.GenericMonospace, 8), new SolidBrush(Color.Black), 10, 44);
                e.Graphics.DrawString("Base Type: "+selected_basetypename, new Font(FontFamily.GenericMonospace, 8), new SolidBrush(Color.Black), 10, 56);
                e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 5, 77, this.Width-5, 77);
            
                e.Graphics.DrawString("Components of Type from IReferenceService:", new Font(FontFamily.GenericMonospace, 8), new SolidBrush(Color.Red), 5, 85);                        
                if( selected_typename != "None selected." )
                    for(int i=0; i<typeComponents.Length; i++)
                        e.Graphics.DrawString(typeComponents[i], new Font(FontFamily.GenericMonospace, 8), new SolidBrush(Color.Black), 20, 97+(i*12));
            
                e.Graphics.DrawString("Components of Base Type from IReferenceService:", new Font(FontFamily.GenericMonospace, 8), new SolidBrush(Color.Red), 5, 109+(typeComponents.Length*12));
                if( selected_typename != "None selected." )
                    for(int i=0; i<basetypeComponents.Length; i++)
                        e.Graphics.DrawString(basetypeComponents[i], new Font(FontFamily.GenericMonospace, 8), new SolidBrush(Color.Black), 20, 121+(typeComponents.Length*12)+(i*12));
            }
    }
}

[C++, JScript] No example is available for C++ or JScript. To view a Visual Basic or C# example, click the Language Filter button in the upper-left corner of the page.

Requirements

Namespace: System.ComponentModel.Design

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: System (in System.dll)

IReferenceService Interface

Remarks

Example

Requirements

See Also