Читати англійською Редагувати

Поділитися через


ServiceContainer Class

Definition

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

public class ServiceContainer : IDisposable, IServiceProvider, System.ComponentModel.Design.IServiceContainer
public sealed class ServiceContainer : IServiceProvider, System.ComponentModel.Design.IServiceContainer
public class ServiceContainer : IDisposable, System.ComponentModel.Design.IServiceContainer
Inheritance
ServiceContainer
Implements

Examples

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.

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 } );
        }

        internal 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.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.
                    using (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.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);
        }		
    }
}

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.

Примітка

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.

Constructors

ServiceContainer()

Initializes a new instance of the ServiceContainer class.

ServiceContainer(IServiceProvider)

Initializes a new instance of the ServiceContainer class using the specified parent service provider.

Properties

DefaultServices

Gets the default services implemented directly by ServiceContainer.

Methods

AddService(Type, Object, Boolean)

Adds the specified service to the service container.

AddService(Type, Object)

Adds the specified service to the service container.

AddService(Type, ServiceCreatorCallback, Boolean)

Adds the specified service to the service container.

AddService(Type, ServiceCreatorCallback)

Adds the specified service to the service container.

Dispose()

Disposes this service container.

Dispose(Boolean)

Disposes this service container.

Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetService(Type)

Gets the requested service.

GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
RemoveService(Type, Boolean)

Removes the specified service type from the service container.

RemoveService(Type)

Removes the specified service type from the service container.

ToString()

Returns a string that represents the current object.

(Inherited from Object)

Applies to

Продукт Версії
.NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1

See also