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ServiceContainer Class

Provides a simple implementation of the IServiceContainer interface. This class cannot be inherited.

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

System.Object
   System.ComponentModel.Design.ServiceContainer

[Visual Basic]
NotInheritable Public Class ServiceContainer
   Implements IServiceContainer, IServiceProvider
[C#]
public sealed class ServiceContainer : IServiceContainer,
   IServiceProvider
[C++]
public __gc __sealed class ServiceContainer : public
   IServiceContainer, IServiceProvider
[JScript]
public class ServiceContainer implements IServiceContainer,
   IServiceProvider

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.

Remarks

The ServiceContainer object can be used to store and provide services. ServiceContainer implements the IServiceContainer interface.

The ServiceContainer object can be created using a constructor that adds a parent IServiceContainer through which services can be optionally added to or removed from all parent IServiceContainer objects, including the immediate parent IServiceContainer. To add or remove a service from all IServiceContainer implementations that are linked to this IServiceContainer through parenting, call the AddService or RemoveService method overload that accepts a Boolean value indicating whether to promote the service request.

Example

[Visual Basic, C#, C++] The following example program demonstrates service chaining and the resultant service availability of a chain of linked ServiceContainer objects. The program provides a user interface that allows you to see the availability of services within a chain of linked services, and uses the AddService, GetService, and RemoveService methods as well as linked service containers.

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

' Example form provides UI for demonstrating service sharing behavior 
' of a network of IServiceContainer/IServiceProvider controls.
Public Class ServiceForm
    Inherits System.Windows.Forms.Form
   
    ' Root service container control for tree.
    Private root As ServiceObjectControl      
    
    ' Button for clearing any provided services and resetting tree states.
    Private WithEvents reset_button As System.Windows.Forms.Button

    ' Color list used to color code controls.
    Private colorkeys() As Color

    ' Strings used to reflect text service.
    Private keystrings() As String          
   
   Public Sub New()
      InitializeComponent()
      CreateServiceControlTree()
      colorkeys = New Color() {Color.Beige, Color.SeaShell, Color.LightGreen, Color.LightBlue, Color.Khaki, Color.CadetBlue}
      keystrings = New String() {"No service use", "Service not accessible", "Service provided", "Service obtained", "Service accessible", "No further access"}
    End Sub

    Private Sub CreateServiceControlTree()
        ' Create root service control.
        Dim control1 As New ServiceObjectControl(Nothing, New Size(300, 40), New Point(10, 80), Me)
        root = control1
        ' Create first tier - pass parent with service object control 1
        Dim control2 As New ServiceObjectControl(control1, New Size(200, 30), New Point(50, 160), Me)
        Dim control3 As New ServiceObjectControl(control1, New Size(200, 30), New Point(50, 240), Me)
        ' Create second tier A - pass parent with service object control 2
        Dim control4 As New ServiceObjectControl(control2, New Size(180, 20), New Point(300, 145), Me)
        Dim control5 As New ServiceObjectControl(control2, New Size(180, 20), New Point(300, 185), Me)
        ' Create second tier B - pass parent with service object control 3
        Dim control6 As New ServiceObjectControl(control3, New Size(180, 20), New Point(300, 225), Me)
        Dim control7 As New ServiceObjectControl(control3, New Size(180, 20), New Point(300, 265), Me)
        ' Add controls.
        Me.Controls.AddRange(New Control() {control1, control2, control3, control4, control5, control6, control7})
    End Sub

    Public Sub ResetServiceTree(ByVal sender As Object, ByVal e As EventArgs) Handles reset_button.Click
        ' Remove the service from the service tree.
        If Not (root.serviceContainer.GetService(GetType(TextService)) Is Nothing) Then
            root.serviceContainer.RemoveService(GetType(TextService), True)
        End If
        ' Set all controls to "not obtained" and clear their labels.
        Dim i As Integer
        For i = 0 To Controls.Count - 1
            If Not Controls(i).Equals(reset_button) Then
                CType(Controls(i), ServiceObjectControl).state = TextServiceState.ServiceNotObtained
                CType(Controls(i), ServiceObjectControl).label = String.Empty
                CType(Controls(i), ServiceObjectControl).BackColor = Color.Beige
            End If
        Next i
    End Sub

    Public Sub UpdateServiceCoverage()
        ' Have each control set state to reflect service availability.
        Dim i As Integer
        For i = 0 To Controls.Count - 1
            If Not Controls(i).Equals(reset_button) Then
                CType(Controls(i), ServiceObjectControl).ReflectServiceVisibility()
            End If
        Next i
    End Sub

    Private Sub InitializeComponent()
        Me.reset_button = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        '
        'reset_button
        '
        Me.reset_button.Location = New System.Drawing.Point(392, 88)
        Me.reset_button.Name = "reset_button"
        Me.reset_button.TabIndex = 0
        Me.reset_button.TabStop = False
        Me.reset_button.Text = "Reset"
        '
        'ServiceForm
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(512, 373)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.reset_button})
        Me.MinimumSize = New System.Drawing.Size(520, 400)
        Me.Name = "ServiceForm"
        Me.Text = "Service Container Architecture Example"
        Me.ResumeLayout(False)

    End Sub

    <STAThread()> _
    Shared Sub Main()
        Application.Run(New ServiceForm())
    End Sub

    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
        e.Graphics.DrawString("The following tree diagram represents a hierarchy of linked service containers in controls.", New Font("Arial", 9), New SolidBrush(Color.Black), 4, 4)
        e.Graphics.DrawString("This example demonstrates the propagation behavior of services through a linked service object tree.", New Font("Arial", 8), New SolidBrush(Color.Black), 4, 26)
        e.Graphics.DrawString("Right-click a component to add or replace a text service, or to remove it if the component provided it.", New Font("Arial", 8), New SolidBrush(Color.Black), 4, 38)
        e.Graphics.DrawString("Left-click a component to update text from the text service if available.", New Font("Arial", 8), New SolidBrush(Color.Black), 4, 50)

        ' Draw lines to represent tree branches.
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 20, 125, 20, 258)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 21, 175, 45, 175)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 21, 258, 45, 258)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 255, 175, 285, 175)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 255, 258, 285, 258)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 285, 155, 285, 195)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 285, 238, 285, 278)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 285, 155, 290, 155)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 285, 195, 290, 195)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 285, 238, 290, 238)
        e.Graphics.DrawLine(New Pen(New SolidBrush(Color.Black), 1), 285, 278, 290, 278)

        ' Draw color key.
        e.Graphics.DrawRectangle(New Pen(New SolidBrush(Color.Black), 1), 20, 305, 410, 60)
        Dim y As Integer = 0
        Dim i As Integer
        For i = 0 To 2
            e.Graphics.FillRectangle(New SolidBrush(colorkeys(y)), 25 + i * 140, 310, 20, 20)
            e.Graphics.DrawRectangle(New Pen(New SolidBrush(Color.Black), 1), 25 + i * 140, 310, 20, 20)
            e.Graphics.DrawString(keystrings(y), New Font("Arial", 8), New SolidBrush(Color.Black), 50 + i * 140, 315)
            y += 1
            e.Graphics.FillRectangle(New SolidBrush(colorkeys(y)), 25 + i * 140, 340, 20, 20)
            e.Graphics.DrawRectangle(New Pen(New SolidBrush(Color.Black), 1), 25 + i * 140, 340, 20, 20)
            e.Graphics.DrawString(keystrings(y), New Font("Arial", 8), New SolidBrush(Color.Black), 50 + i * 140, 345)
            y += 1
        Next i
    End Sub
End Class

' An example user control that uses ServiceContainer to add, remove, 
' and access services through a linkable service container network.
Public Class ServiceObjectControl
    Inherits System.Windows.Forms.UserControl

    ' This example user control implementation provides a wrapper for 
    ' ServiceContainer, supporting a linked service container network.
    Public serviceContainer As serviceContainer
    ' Parent form reference for main program function access.
    Private parentserviceForm As ServiceForm
    ' String for label displayed on the control to indicate the 
    ' control's current service-related configuration state.
    Public label As String    
    ' The current state of the control reflecting whether it has 
    ' obtained or provided a text service.
    Private state_ As TextServiceState
    Public Property state() As TextServiceState
        Get
            Return state_
        End Get
        Set(ByVal Value As TextServiceState)
            If CType(Value, TextServiceState) = TextServiceState.ServiceProvided Then
                Me.BackColor = Color.LightGreen
            ElseIf CType(Value, TextServiceState) = TextServiceState.ServiceNotObtained Then
                Me.BackColor = Color.White
            ElseIf CType(Value, TextServiceState) = TextServiceState.ServiceObtained Then
                Me.BackColor = Color.LightBlue
            ElseIf CType(Value, TextServiceState) = TextServiceState.ServiceNotFound Then
                Me.BackColor = Color.SeaShell
            End If
            state_ = Value
        End Set
    End Property    

    Public Sub New(ByVal serviceContainerParent As ServiceObjectControl, ByVal size As Size, ByVal location As Point, ByVal parent As ServiceForm)
        Me.state_ = TextServiceState.ServiceNotObtained
        Me.BackColor = Color.Beige
        Me.label = String.Empty
        Me.Size = size
        Me.Location = location
        Me.parentserviceForm = parent        
        If serviceContainerParent Is Nothing Then
            serviceContainer = New ServiceContainer()
        Else
            serviceContainer = New ServiceContainer(serviceContainerParent.serviceContainer)
        End If
    End Sub

    ' Paint method override draws the label string on the control.
    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
        e.Graphics.DrawString(label, New Font("Arial", 8), New SolidBrush(Color.Black), 5, 5)
    End Sub

    ' Process mouse-down behavior for click.
    Protected Overrides Sub OnMouseDown(ByVal e As System.Windows.Forms.MouseEventArgs)
        If e.Button = MouseButtons.Left Then
            If state_ <> TextServiceState.ServiceProvided Then
                ' Attempt to update text from service, and set color 
                ' state accordingly.
                Dim ts As TextService = CType(serviceContainer.GetService(GetType(TextService)), TextService)
                If Not (ts Is Nothing) Then
                    Me.label = ts.text
                    state = TextServiceState.ServiceObtained
                Else
                    Me.label = "Service Not Found"
                    state = TextServiceState.ServiceNotFound
                End If
            End If
        End If
        If e.Button = MouseButtons.Right Then
            If state_ = TextServiceState.ServiceProvided Then
                ' Remove service if the container provided it.
                If Not (serviceContainer.GetService(GetType(TextService)) Is Nothing) Then
                    serviceContainer.RemoveService(GetType(TextService), True)
                    state = TextServiceState.ServiceNotObtained
                    Me.label = "Service Removed"
                End If
            Else
                ' Obtain string and provide text service.
                Dim form As New StringInputDialog("Test String")
                form.StartPosition = FormStartPosition.CenterParent
                If form.ShowDialog() = DialogResult.OK Then
                    If Not (serviceContainer.GetService(GetType(TextService)) Is Nothing) Then
                        serviceContainer.RemoveService(GetType(TextService), True)
                    End If
                    parentserviceForm.ResetServiceTree(Me, New EventArgs())
                    serviceContainer.AddService(GetType(TextService), New TextService(form.inputTextBox.Text), True)
                    state = TextServiceState.ServiceProvided
                    Me.label = "Provided Text: " + form.inputTextBox.Text
                End If
            End If
        End If
        parentserviceForm.UpdateServiceCoverage()
    End Sub

    ' Method accesses the TextService to test the visibility of the service 
    ' from the control, and sets the UI state accordingly.
    Public Sub ReflectServiceVisibility()
        If state_ = TextServiceState.ServiceObtained Then
            If serviceContainer.GetService(GetType(TextService)) Is Nothing Then
                Me.BackColor = Color.CadetBlue
            End If
        ElseIf state_ <> TextServiceState.ServiceProvided Then
            If serviceContainer.GetService(GetType(TextService)) Is Nothing Then
                Me.BackColor = Color.White
                Return
            End If

            ' Service available.                   
            If state_ = TextServiceState.ServiceNotFound Then
                Me.BackColor = Color.Khaki
            ElseIf state_ = TextServiceState.ServiceNotObtained AndAlso label <> "Service Removed" Then
                Me.BackColor = Color.Khaki
            End If
        End If
    End Sub

End Class

' Example service type contains a text string, sufficient 
' for use to demonstrate service sharing.
Public Class TextService
    Public [text] As String

    Public Sub New()
        MyClass.New(String.Empty)
    End Sub

    Public Sub New(ByVal [text] As String)
        Me.text = [text]
    End Sub
End Class

Public Enum TextServiceState
    ServiceNotObtained
    ServiceObtained
    ServiceProvided
    ServiceNotFound
End Enum

' Example Form for entering a string.
Friend Class StringInputDialog
    Inherits System.Windows.Forms.Form

    Private ok_button As System.Windows.Forms.Button
    Private cancel_button As System.Windows.Forms.Button
    Public inputTextBox As System.Windows.Forms.TextBox

    Public Sub New(ByVal [text] As String)
        InitializeComponent()
        inputTextBox.Text = [text]
    End Sub

    Private Sub InitializeComponent()
        Me.ok_button = New System.Windows.Forms.Button()
        Me.cancel_button = New System.Windows.Forms.Button()
        Me.inputTextBox = New System.Windows.Forms.TextBox()
        Me.SuspendLayout()
        Me.ok_button.Anchor = System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Right
        Me.ok_button.Location = New System.Drawing.Point(180, 43)
        Me.ok_button.Name = "ok_button"
        Me.ok_button.TabIndex = 1
        Me.ok_button.Text = "OK"
        Me.ok_button.DialogResult = System.Windows.Forms.DialogResult.OK
        Me.cancel_button.Anchor = System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Right
        Me.cancel_button.Location = New System.Drawing.Point(260, 43)
        Me.cancel_button.Name = "cancel_button"
        Me.cancel_button.TabIndex = 2
        Me.cancel_button.Text = "Cancel"
        Me.cancel_button.DialogResult = System.Windows.Forms.DialogResult.Cancel
        Me.inputTextBox.Location = New System.Drawing.Point(6, 9)
        Me.inputTextBox.Name = "inputTextBox"
        Me.inputTextBox.Size = New System.Drawing.Size(327, 20)
        Me.inputTextBox.TabIndex = 0
        Me.inputTextBox.Text = ""
        Me.inputTextBox.Anchor = System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left Or System.Windows.Forms.AnchorStyles.Right
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(342, 73)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.inputTextBox, Me.cancel_button, Me.ok_button})
        Me.MinimumSize = New System.Drawing.Size(350, 100)
        Me.Name = "StringInputDialog"
        Me.Text = "Text Service Provide String Dialog"
        Me.ResumeLayout(False)
    End Sub

End Class

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

namespace ServiceArchitectureExample
{
    // Example form provides UI for demonstrating service sharing behavior 
    // of a network of IServiceContainer/IServiceProvider controls.
    public class ServiceForm : System.Windows.Forms.Form
    {                
        // Root service container control for tree.
        private ServiceObjectControl root;         
             
        // Button for clearing any provided services and resetting tree states.
        private System.Windows.Forms.Button reset_button;       

        // Color list used to color code controls.
        private Color[] colorkeys;                              

        // Strings used to reflect text service.
        private string[] keystrings;                            

        public ServiceForm()
        {
            InitializeComponent();
            CreateServiceControlTree();
            colorkeys = new Color[] { Color.Beige, Color.SeaShell, Color.LightGreen, Color.LightBlue, Color.Khaki, Color.CadetBlue };
            keystrings = new string[] { "No service use", "Service not accessible", "Service provided", "Service obtained", "Service accessible", "No further access" };
        }

        private void CreateServiceControlTree()
        {
            // Create root service control.
            ServiceObjectControl control1 = new ServiceObjectControl(null, new Size(300, 40), new Point(10, 80), this);
            root = control1;
            // Create first tier - pass parent with service object control 1
            ServiceObjectControl control2 = new ServiceObjectControl(control1, new Size(200, 30), new Point(50, 160), this);
            ServiceObjectControl control3 = new ServiceObjectControl(control1, new Size(200, 30), new Point(50, 240), this);
            // Create second tier A - pass parent with service object control 2
            ServiceObjectControl control4 = new ServiceObjectControl(control2, new Size(180, 20), new Point(300, 145), this);
            ServiceObjectControl control5 = new ServiceObjectControl(control2, new Size(180, 20), new Point(300, 185), this);
            // Create second tier B - pass parent with service object control 3
            ServiceObjectControl control6 = new ServiceObjectControl(control3, new Size(180, 20), new Point(300, 225), this);
            ServiceObjectControl control7 = new ServiceObjectControl(control3, new Size(180, 20), new Point(300, 265), this);
            // Add controls.
            this.Controls.AddRange( new Control[] { control1, control2, control3, control4, control5, control6, control7 } );
        }

        public void ResetServiceTree(object sender, EventArgs e)
        {
            // Remove the service from the service tree.
            if( root.serviceContainer.GetService(typeof(TextService)) != null )            
                root.serviceContainer.RemoveService(typeof(TextService), true);

            // Set all controls to "not obtained" and clear their labels.
            for( int i=0; i<Controls.Count; i++ )
                if( !Controls[i].Equals(reset_button) ) 
                {
                    ((ServiceObjectControl)Controls[i]).state = TextServiceState.ServiceNotObtained;
                    ((ServiceObjectControl)Controls[i]).label = string.Empty;
                    ((ServiceObjectControl)Controls[i]).BackColor = Color.Beige;
                }
        }

        public void UpdateServiceCoverage()
        {
            // Have each control set state to reflect service availability.
            for( int i=0; i<Controls.Count; i++ )
                if( !Controls[i].Equals(reset_button) )                 
                    ((ServiceObjectControl)Controls[i]).ReflectServiceVisibility();                                 
        }

        #region Windows Form Designer generated code
        private void InitializeComponent()
        {
            this.reset_button = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // reset_button
            // 
            this.reset_button.Location = new System.Drawing.Point(392, 88);
            this.reset_button.Name = "reset_button";
            this.reset_button.TabIndex = 0;
            this.reset_button.TabStop = false;
            this.reset_button.Text = "Reset";
            this.reset_button.Click += new System.EventHandler(this.ResetServiceTree);
            // 
            // ServiceForm
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(512, 373);
            this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                          this.reset_button});
            this.MinimumSize = new System.Drawing.Size(520, 400);
            this.Name = "ServiceForm";
            this.Text = "Service Container Architecture Example";
            this.ResumeLayout(false);

        }
        #endregion

        [STAThread]
        static void Main() 
        {
            Application.Run(new ServiceForm());
        }

        protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
        {            
            e.Graphics.DrawString("The following tree diagram represents a hierarchy of linked service containers in controls.", new Font("Arial", 9), new SolidBrush(Color.Black), 4, 4);
            e.Graphics.DrawString("This example demonstrates the propagation behavior of services through a linked service object tree.", new Font("Arial", 8), new SolidBrush(Color.Black), 4, 26);            
            e.Graphics.DrawString("Right-click a component to add or replace a text service, or to remove it if the component provided it.", new Font("Arial", 8), new SolidBrush(Color.Black), 4, 38);
            e.Graphics.DrawString("Left-click a component to update text from the text service if available.", new Font("Arial", 8), new SolidBrush(Color.Black), 4, 50);

            // Draw lines to represent tree branches.
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 20, 125, 20, 258);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 21, 175, 45, 175);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 21, 258, 45, 258);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 255, 175, 285, 175);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 255, 258, 285, 258);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 285, 155, 285, 195);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 285, 238, 285, 278);            
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 285, 155, 290, 155);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 285, 195, 290, 195);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 285, 238, 290, 238);
            e.Graphics.DrawLine(new Pen(new SolidBrush(Color.Black), 1), 285, 278, 290, 278);

            // Draw color key.
            e.Graphics.DrawRectangle(new Pen(new SolidBrush(Color.Black), 1), 20, 305, 410, 60);
            int y=0;
            for( int i=0; i<3; i++ )
            {
                e.Graphics.FillRectangle(new SolidBrush(colorkeys[y]), 25+(i*140), 310, 20, 20);           
                e.Graphics.DrawRectangle(new Pen(new SolidBrush(Color.Black), 1), 25+(i*140), 310, 20, 20);     
                e.Graphics.DrawString(keystrings[y], new Font("Arial", 8), new SolidBrush(Color.Black), 50+(i*140), 315);
                y++;
                e.Graphics.FillRectangle(new SolidBrush(colorkeys[y]), 25+(i*140), 340, 20, 20);           
                e.Graphics.DrawRectangle(new Pen(new SolidBrush(Color.Black), 1), 25+(i*140), 340, 20, 20);              
                e.Graphics.DrawString(keystrings[y], new Font("Arial", 8), new SolidBrush(Color.Black), 50+(i*140), 345);
                y++;
            }
        }
    }

    // An example user control that uses ServiceContainer to add, remove,
    // and access services through a linkable service container network.
    public class ServiceObjectControl : System.Windows.Forms.UserControl
    {
        // This example user control implementation provides a wrapper for 
        // ServiceContainer, supporting a linked service container network.    
        public ServiceContainer serviceContainer;        
        // Parent form reference for main program function access.
        private ServiceForm parent;                  
        // String for label displayed on the control to indicate the 
        // control's current service-related configuration state.
        public string label;               
        // The current state of the control reflecting whether it has 
        // obtained or provided a text service.
        private TextServiceState state_;
        public TextServiceState state
        {
            get
            {
                return state_;
            }
            set
            {
                if( (TextServiceState)value == TextServiceState.ServiceProvided )
                    this.BackColor = Color.LightGreen;
                else if( (TextServiceState)value == TextServiceState.ServiceNotObtained )                
                    this.BackColor = Color.White;                                   
                else if( (TextServiceState)value == TextServiceState.ServiceObtained )
                    this.BackColor = Color.LightBlue;
                else if( (TextServiceState)value == TextServiceState.ServiceNotFound )                                    
                    this.BackColor = Color.SeaShell;                
                state_ = value;
            }
        }        
        
        public ServiceObjectControl(ServiceObjectControl serviceContainerParent, Size size, Point location, ServiceForm parent)
        {
            this.state_ = TextServiceState.ServiceNotObtained;
            this.BackColor = Color.Beige;            
            this.label = string.Empty;            
            this.Size = size;
            this.Location = location;
            this.parent = parent;            
            if( serviceContainerParent == null )
                serviceContainer = new ServiceContainer();
            else
                serviceContainer = new ServiceContainer(serviceContainerParent.serviceContainer);
        }

        // Paint method override draws the label string on the control.
        protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
        {
            e.Graphics.DrawString(label, new Font("Arial", 8), new SolidBrush(Color.Black), 5, 5);            
        }

        // Process mouse-down behavior for click.
        protected override void OnMouseDown(System.Windows.Forms.MouseEventArgs e)
        {
            if( e.Button == MouseButtons.Left )
            {
                if( state_ != TextServiceState.ServiceProvided )
                {
                    // Attempt to update text from service, and set color 
                    // state accordingly.
                    TextService ts = (TextService)serviceContainer.GetService(typeof(TextService));
                    if( ts != null )
                    {
                        this.label = ts.text;
                        state = TextServiceState.ServiceObtained;
                    }
                    else
                    {                    
                        this.label = "Service Not Found";                        
                        state = TextServiceState.ServiceNotFound;
                    }
                }
            }
            if( e.Button == MouseButtons.Right )
            {
                if( state_ == TextServiceState.ServiceProvided )
                {
                    // Remove service if the container provided it.
                    if( serviceContainer.GetService(typeof(TextService)) != null )
                    {
                        serviceContainer.RemoveService(typeof(TextService), true);
                        state = TextServiceState.ServiceNotObtained; 
                        this.label = "Service Removed";                                                                   
                    }                    
                }
                else
                {
                    // Obtain string and provide text service.
                    StringInputDialog form = new StringInputDialog("Test String");
                    form.StartPosition = FormStartPosition.CenterParent;
                    if( form.ShowDialog() == DialogResult.OK )
                    {
                        if( serviceContainer.GetService(typeof(TextService)) != null )                        
                            serviceContainer.RemoveService(typeof(TextService), true);                                                                            
                        parent.ResetServiceTree(this, new EventArgs());
                        serviceContainer.AddService(typeof(TextService), new TextService( form.inputTextBox.Text ), true);
                        state = TextServiceState.ServiceProvided;
                        this.label = "Provided Text: "+form.inputTextBox.Text;                                 
                    }
                }
            }
            parent.UpdateServiceCoverage();
        }

        // Method accesses the TextService to test the visibility of the service 
        // from the control, and sets the UI state accordingly.
        public void ReflectServiceVisibility()
        {
            if( state_ == TextServiceState.ServiceObtained )
            {
                if( serviceContainer.GetService(typeof(TextService)) == null )  
                    this.BackColor = Color.CadetBlue;
            }
            else if( state_ != TextServiceState.ServiceProvided )
            {
                if( serviceContainer.GetService(typeof(TextService)) == null )
                {
                    this.BackColor = Color.White;
                    return;
                }

                // Service available.                  
                if( state_ == TextServiceState.ServiceNotFound )                
                    this.BackColor = Color.Khaki;                
                else if( state_ == TextServiceState.ServiceNotObtained && label != "Service Removed" )
                    this.BackColor = Color.Khaki;       
            }            
        }
    }

    // Example service type contains a text string, sufficient 
    // to demonstrate service sharing.
    public class TextService
    {
        public string text;

        public TextService() : this(string.Empty)
        {
        }

        public TextService(string text)
        {
            this.text = text;
        }
    }

    public enum TextServiceState
    {
        ServiceNotObtained,
        ServiceObtained,
        ServiceProvided,
        ServiceNotFound
    }

    // Example Form for entering a string.
    internal class StringInputDialog : System.Windows.Forms.Form
    {
        private System.Windows.Forms.Button ok_button;
        private System.Windows.Forms.Button cancel_button;
        public System.Windows.Forms.TextBox inputTextBox;

        public StringInputDialog(string text)
        {
            InitializeComponent();
            inputTextBox.Text = text;
        }

        private void InitializeComponent()
        {
            this.ok_button = new System.Windows.Forms.Button();
            this.cancel_button = new System.Windows.Forms.Button();
            this.inputTextBox = new System.Windows.Forms.TextBox();
            this.SuspendLayout();
            this.ok_button.Anchor = (System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right);
            this.ok_button.Location = new System.Drawing.Point(180, 43);
            this.ok_button.Name = "ok_button";
            this.ok_button.TabIndex = 1;
            this.ok_button.Text = "OK";      
            this.ok_button.DialogResult = System.Windows.Forms.DialogResult.OK;            
            this.cancel_button.Anchor = (System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right);
            this.cancel_button.Location = new System.Drawing.Point(260, 43);
            this.cancel_button.Name = "cancel_button";
            this.cancel_button.TabIndex = 2;
            this.cancel_button.Text = "Cancel";            
            this.cancel_button.DialogResult = System.Windows.Forms.DialogResult.Cancel;
            this.inputTextBox.Location = new System.Drawing.Point(6, 9);
            this.inputTextBox.Name = "inputTextBox";
            this.inputTextBox.Size = new System.Drawing.Size(327, 20);
            this.inputTextBox.TabIndex = 0;
            this.inputTextBox.Text = "";            
            this.inputTextBox.Anchor = ((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
                | System.Windows.Forms.AnchorStyles.Right);
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(342, 73);
            this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                          this.inputTextBox,
                                                                          this.cancel_button,
                                                                          this.ok_button});
            this.MinimumSize = new System.Drawing.Size(350, 100);
            this.Name = "StringInputDialog";
            this.Text = "Text Service Provide String Dialog";
            this.ResumeLayout(false);
        }        
    }
}

[C++] 
#using <mscorlib.dll>
#using <System.Windows.Forms.dll>
#using <System.dll>
#using <System.Drawing.dll>
using namespace System;
using namespace System::Drawing;
using namespace System::Collections;
using namespace System::ComponentModel;
using namespace System::ComponentModel::Design;
using namespace System::Windows::Forms;
using namespace System::Windows::Forms::Design;

public __gc class ServiceObjectControl;

// Example form provides UI for demonstrating service sharing behavior
// of a network of IServiceContainer/IServiceProvider controls.
public __gc class ServiceForm : public System::Windows::Forms::Form
{
    // Root service container control for tree.
private:
    ServiceObjectControl* root;

    // Button for clearing any provided services and resetting tree states.
    System::Windows::Forms::Button* reset_button;

    // Color list used to color code controls.
    Color colorkeys[];

    // Strings used to reflect text service.
    String* keystrings[];

public:
    ServiceForm()
    {
        InitializeComponent();
        CreateServiceControlTree();
        colorkeys = new Color[6];
        colorkeys[0] = Color::Beige;
        colorkeys[1] = Color::SeaShell;
        colorkeys[2] = Color::LightGreen;
        colorkeys[3] = Color::LightBlue;
        colorkeys[4] = Color::Khaki;
        colorkeys[5] = Color::CadetBlue;
        String* stringstemp[] = { S"No service use", S"Service not accessible", S"Service provided", S"Service obtained", S"Service accessible", S"No further access" };
        keystrings = stringstemp;
    }

private:
    void CreateServiceControlTree();
    void InitializeComponent();
public:
    void ResetServiceTree(Object* sender, EventArgs* e);
    void UpdateServiceCoverage();
protected:
    void OnPaint(System::Windows::Forms::PaintEventArgs* e);
};

// Example service type contains a text string, sufficient
// to demonstrate service sharing.
public __gc class TextService
{
public:
    String* text;

    TextService() : text(String::Empty)
    {
    }

    TextService(String* text)
    {
        this->text = text;
    }
};

public __value enum TextServiceState
{
    ServiceNotObtained,
    ServiceObtained,
    ServiceProvided,
    ServiceNotFound
};

// Example Form for entering a string.
private __gc class StringInputDialog : public System::Windows::Forms::Form
{
private:
    System::Windows::Forms::Button* ok_button;
    System::Windows::Forms::Button* cancel_button;
public:
    System::Windows::Forms::TextBox* inputTextBox;

    StringInputDialog(String* text)
    {
        InitializeComponent();
        inputTextBox->Text = text;
    }

private:
    void InitializeComponent()
    {
        this->ok_button = new System::Windows::Forms::Button();
        this->cancel_button = new System::Windows::Forms::Button();
        this->inputTextBox = new System::Windows::Forms::TextBox();
        this->SuspendLayout();
        this->ok_button->Anchor = static_cast<AnchorStyles>(System::Windows::Forms::AnchorStyles::Bottom | System::Windows::Forms::AnchorStyles::Right);
        this->ok_button->Location = System::Drawing::Point(180, 43);
        this->ok_button->Name = S"ok_button";
        this->ok_button->TabIndex = 1;
        this->ok_button->Text = S"OK";
        this->ok_button->DialogResult = System::Windows::Forms::DialogResult::OK;
        this->cancel_button->Anchor = static_cast<AnchorStyles>(System::Windows::Forms::AnchorStyles::Bottom | System::Windows::Forms::AnchorStyles::Right);
        this->cancel_button->Location = System::Drawing::Point(260, 43);
        this->cancel_button->Name = S"cancel_button";
        this->cancel_button->TabIndex = 2;
        this->cancel_button->Text = S"Cancel";
        this->cancel_button->DialogResult = System::Windows::Forms::DialogResult::Cancel;
        this->inputTextBox->Location = System::Drawing::Point(6, 9);
        this->inputTextBox->Name = S"inputTextBox";
        this->inputTextBox->Size = System::Drawing::Size(327, 20);
        this->inputTextBox->TabIndex = 0;
        this->inputTextBox->Text = S"";
        this->inputTextBox->Anchor = static_cast<AnchorStyles>((System::Windows::Forms::AnchorStyles::Top | System::Windows::Forms::AnchorStyles::Left)
            | System::Windows::Forms::AnchorStyles::Right);
        this->AutoScaleBaseSize = System::Drawing::Size(5, 13);
        this->ClientSize = System::Drawing::Size(342, 73);

        System::Windows::Forms::Control* temp0 [] = {this->inputTextBox,
            this->cancel_button,
            this->ok_button};

        this->Controls->AddRange(temp0);
        this->MinimumSize = System::Drawing::Size(350, 100);
        this->Name = S"StringInputDialog";
        this->Text = S"Text Service Provide String Dialog";
        this->ResumeLayout(false);
    }
};

// An example user control that uses ServiceContainer to add, remove,
// and access services through a linkable service container network.
public __gc class ServiceObjectControl : public System::Windows::Forms::UserControl
{
    // This example user control implementation provides a wrapper for
    // ServiceContainer, supporting a linked service container network.
public:
    ServiceContainer* serviceContainer;
    // Parent form reference for main program function access.
private:
    ServiceForm* parent;
    // String for label displayed on the control to indicate the
    // control's current service-related configuration state.
public:
    String* label;
    // The current state of the control reflecting whether it has
    // obtained or provided a text service.
private:
    TextServiceState state_;
public:
    __property TextServiceState get_state()
    {
        return state_;
    }

    __property void set_state( TextServiceState value )
    {
        if( (TextServiceState)value == TextServiceState::ServiceProvided )
            this->BackColor = Color::LightGreen;
        else if( (TextServiceState)value == TextServiceState::ServiceNotObtained )
            this->BackColor = Color::White;
        else if( (TextServiceState)value == TextServiceState::ServiceObtained )
            this->BackColor = Color::LightBlue;
        else if( (TextServiceState)value == TextServiceState::ServiceNotFound )
            this->BackColor = Color::SeaShell;
        state_ = value;
    }

    ServiceObjectControl(ServiceObjectControl* serviceContainerParent, System::Drawing::Size size, Point location, ServiceForm* parent)
    {
        this->state_ = TextServiceState::ServiceNotObtained;
        this->BackColor = Color::Beige;
        this->label = String::Empty;
        this->Size = size;
        this->Location = location;
        this->parent = parent;
        if( serviceContainerParent == 0 )
            serviceContainer = new ServiceContainer();
        else
            serviceContainer = new ServiceContainer(serviceContainerParent->serviceContainer);
    }

    // Paint method override draws the label string on the control.
protected:
    void OnPaint(System::Windows::Forms::PaintEventArgs* e)
    {
        e->Graphics->DrawString(label, new System::Drawing::Font(S"Arial", 8), new SolidBrush(Color::Black), 5, 5);
    }

    // Process mouse-down behavior for click.
    void OnMouseDown(System::Windows::Forms::MouseEventArgs* e)
    {
        if( e->Button == MouseButtons::Left )
        {
            if( state_ != TextServiceState::ServiceProvided )
            {
                // Attempt to update text from service, and set color
                // state accordingly.
                TextService* ts = dynamic_cast<TextService*>(serviceContainer->GetService(__typeof(TextService)));
                if( ts != 0 )
                {
                    this->label = ts->text;
                    state = TextServiceState::ServiceObtained;
                }
                else
                {
                    this->label = S"Service Not Found";
                    state = TextServiceState::ServiceNotFound;
                }
            }
        }
        if( e->Button == MouseButtons::Right )
        {
            if( state_ == TextServiceState::ServiceProvided )
            {
                // Remove service if the container provided it.
                if( serviceContainer->GetService(__typeof(TextService)) != 0 )
                {
                    serviceContainer->RemoveService(__typeof(TextService), true);
                    state = TextServiceState::ServiceNotObtained;
                    this->label = S"Service Removed";
                }
            }
            else
            {
                // Obtain string and provide text service.
                StringInputDialog* form = new StringInputDialog(S"Test String");
                form->StartPosition = FormStartPosition::CenterParent;
                if( form->ShowDialog() == DialogResult::OK )
                {
                    if( serviceContainer->GetService(__typeof(TextService)) != 0 )
                        serviceContainer->RemoveService(__typeof(TextService), true);
                    parent->ResetServiceTree(this, new EventArgs());
                    serviceContainer->AddService(__typeof(TextService), new TextService( form->inputTextBox->Text ), true);
                    state = TextServiceState::ServiceProvided;
                    this->label = String::Format( S"Provided Text: {0}", form->inputTextBox->Text );
                }
            }
        }
        parent->UpdateServiceCoverage();
    }

    // Method accesses the TextService to test the visibility of the service
    // from the control, and sets the UI state accordingly.
public:
    void ReflectServiceVisibility()
    {
        if( state_ == TextServiceState::ServiceObtained )
        {
            if( serviceContainer->GetService(__typeof(TextService)) == 0 )
                this->BackColor = Color::CadetBlue;
        }
        else if( state_ != TextServiceState::ServiceProvided )
        {
            if( serviceContainer->GetService(__typeof(TextService)) == 0 )
            {
                this->BackColor = Color::White;
                return;
            }

            // Service available.
            if( state_ == TextServiceState::ServiceNotFound )
                this->BackColor = Color::Khaki;
            else if( state_ == TextServiceState::ServiceNotObtained && !label->Equals(S"Service Removed") )
                this->BackColor = Color::Khaki;
        }
    }
};

void ServiceForm::CreateServiceControlTree()
{
    // Create root service control.
    ServiceObjectControl* control1 = new ServiceObjectControl(0, System::Drawing::Size(300, 40), Point(10, 80), this);
    root = control1;
    // Create first tier - pass parent with service object control 1
    ServiceObjectControl* control2 = new ServiceObjectControl(control1, System::Drawing::Size(200, 30), Point(50, 160), this);
    ServiceObjectControl* control3 = new ServiceObjectControl(control1, System::Drawing::Size(200, 30), Point(50, 240), this);
    // Create second tier A - pass parent with service object control 2
    ServiceObjectControl* control4 = new ServiceObjectControl(control2, System::Drawing::Size(180, 20), Point(300, 145), this);
    ServiceObjectControl* control5 = new ServiceObjectControl(control2, System::Drawing::Size(180, 20), Point(300, 185), this);
    // Create second tier B - pass parent with service object control 3
    ServiceObjectControl* control6 = new ServiceObjectControl(control3, System::Drawing::Size(180, 20), Point(300, 225), this);
    ServiceObjectControl* control7 = new ServiceObjectControl(control3, System::Drawing::Size(180, 20), Point(300, 265), this);
    // Add controls.

    Control* temp1 [] = {control1, control2, control3, control4, control5, control6, control7};

    this->Controls->AddRange( temp1 );
}

void ServiceForm::ResetServiceTree(Object* /*sender*/, EventArgs* /*e*/)
{
    // Remove the service from the service tree.
    if( root->serviceContainer->GetService(__typeof(TextService)) != 0 )
        root->serviceContainer->RemoveService(__typeof(TextService), true);

    // Set all controls to "not obtained" and clear their labels.
    for( int i=0; i<Controls->Count; i++ )
        if( !Controls->Item[i]->Equals(reset_button) )
        {
            (dynamic_cast<ServiceObjectControl*>(Controls->Item[i]))->state = TextServiceState::ServiceNotObtained;
            (dynamic_cast<ServiceObjectControl*>(Controls->Item[i]))->label = String::Empty;
            (dynamic_cast<ServiceObjectControl*>(Controls->Item[i]))->BackColor = Color::Beige;
        }
}

void ServiceForm::UpdateServiceCoverage()
{
    // Have each control set state to reflect service availability.
    for( int i=0; i<Controls->Count; i++ )
        if( !Controls->Item[i]->Equals(reset_button) )
            (dynamic_cast<ServiceObjectControl*>(Controls->Item[i]))->ReflectServiceVisibility();
}

void ServiceForm::InitializeComponent()
{
    this->reset_button = new System::Windows::Forms::Button();
    this->SuspendLayout();
    //
    // reset_button
    //
    this->reset_button->Location = System::Drawing::Point(392, 88);
    this->reset_button->Name = S"reset_button";
    this->reset_button->TabIndex = 0;
    this->reset_button->TabStop = false;
    this->reset_button->Text = S"Reset";
    this->reset_button->Click += new System::EventHandler(this, &ServiceForm::ResetServiceTree);
    //
    // ServiceForm
    //
    this->AutoScaleBaseSize = System::Drawing::Size(5, 13);
    this->ClientSize = System::Drawing::Size(512, 373);

    System::Windows::Forms::Control* temp2 [] = {this->reset_button};

    this->Controls->AddRange(temp2);
    this->MinimumSize = System::Drawing::Size(520, 400);
    this->Name = S"ServiceForm";
    this->Text = S"Service Container Architecture Example";
    this->ResumeLayout(false);

}

void ServiceForm::OnPaint(System::Windows::Forms::PaintEventArgs* e)
{
    e->Graphics->DrawString(S"The following tree diagram represents a hierarchy of linked service containers in controls.", new System::Drawing::Font(S"Arial", 9), new SolidBrush(Color::Black), 4, 4);
    e->Graphics->DrawString(S"This example demonstrates the propagation behavior of services through a linked service object tree.", new System::Drawing::Font(S"Arial", 8), new SolidBrush(Color::Black), 4, 26);
    e->Graphics->DrawString(S"Right-click a component to add or replace a text service, or to remove it if the component provided it.", new System::Drawing::Font(S"Arial", 8), new SolidBrush(Color::Black), 4, 38);
    e->Graphics->DrawString(S"Left-click a component to update text from the text service if available.", new System::Drawing::Font(S"Arial", 8), new SolidBrush(Color::Black), 4, 50);

    // Draw lines to represent tree branches.
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 20, 125, 20, 258);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 21, 175, 45, 175);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 21, 258, 45, 258);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 255, 175, 285, 175);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 255, 258, 285, 258);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 285, 155, 285, 195);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 285, 238, 285, 278);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 285, 155, 290, 155);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 285, 195, 290, 195);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 285, 238, 290, 238);
    e->Graphics->DrawLine(new Pen(new SolidBrush(Color::Black), 1), 285, 278, 290, 278);

    // Draw color key.
    e->Graphics->DrawRectangle(new Pen(new SolidBrush(Color::Black), 1), 20, 305, 410, 60);
    int y=0;
    for( int i=0; i<3; i++ )
    {
        e->Graphics->FillRectangle(new SolidBrush(colorkeys[y]), 25+(i*140), 310, 20, 20);
        e->Graphics->DrawRectangle(new Pen(new SolidBrush(Color::Black), 1), 25+(i*140), 310, 20, 20);
        e->Graphics->DrawString(keystrings[y], new System::Drawing::Font(S"Arial", 8), new SolidBrush(Color::Black), (float)50+(i*140), 315);
        y++;
        e->Graphics->FillRectangle(new SolidBrush(colorkeys[y]), 25+(i*140), 340, 20, 20);
        e->Graphics->DrawRectangle(new Pen(new SolidBrush(Color::Black), 1), 25+(i*140), 340, 20, 20);
        e->Graphics->DrawString(keystrings[y], new System::Drawing::Font(S"Arial", 8), new SolidBrush(Color::Black), (float)50+(i*140), 345);
        y++;
    }
}

[STAThread]
int main()
{
    Application::Run(new ServiceForm());
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter 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)

See Also

ServiceContainer Members | System.ComponentModel.Design Namespace | IServiceProvider | IServiceContainer | ServiceCreatorCallback

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