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ServiceContainer Class

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

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

'Declaration
<HostProtectionAttribute(SecurityAction.LinkDemand, SharedState := True)> _
Public Class ServiceContainer _
	Implements IServiceContainer, IServiceProvider, IDisposable
'Usage
Dim instance As ServiceContainer

NoteNote:

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

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.

NoteNote:

The HostProtectionAttribute attribute applied to this class has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

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.

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 

    Friend Sub ResetServiceTree(ByVal sender As Object, ByVal e As EventArgs) Handles reset_button.Click
        ' Remove the service from the service tree. 
        If (root.serviceContainer.GetService(GetType(TextService)) IsNot 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.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 = System.Windows.Forms.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 (ts IsNot 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 = System.Windows.Forms.MouseButtons.Right Then 
            If state_ = TextServiceState.ServiceProvided Then 
                ' Remove service if the container provided it. 
                If (serviceContainer.GetService(GetType(TextService)) IsNot Nothing) Then
                    serviceContainer.RemoveService(GetType(TextService), True)
                    state = TextServiceState.ServiceNotObtained
                    Me.label = "Service Removed" 
                End If 
            Else 
                ' Obtain string and provide text service. 
                Using form As New StringInputDialog("Test String")
                    form.StartPosition = FormStartPosition.CenterParent
                    If form.ShowDialog() = DialogResult.OK Then 
                        If (serviceContainer.GetService(GetType(TextService)) IsNot 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 Using 
            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.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

System.Object
  System.ComponentModel.Design.ServiceContainer

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

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.

.NET Framework

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