DesignSurfaceManager.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Designer / Host / DesignSurfaceManager.cs / 1 / DesignSurfaceManager.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.ComponentModel.Design { 
 
    using System;
    using System.Collections; 
    using System.ComponentModel;
    using System.ComponentModel.Design;
    using System.Design;
    using System.Diagnostics; 

    ///  
    ///  
    ///     A service container that supports "fixed" services.  Fixed
    ///     services cannot be removed. 
    /// 
    [System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.InheritanceDemand, Name="FullTrust")]
    [System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.LinkDemand, Name="FullTrust")]
    public class DesignSurfaceManager : IServiceProvider, IDisposable { 

        private IServiceProvider                        _parentProvider; 
        private ServiceContainer                        _serviceContainer; 
        private ActiveDesignSurfaceChangedEventHandler  _activeDesignSurfaceChanged;
        private DesignSurfaceEventHandler               _designSurfaceCreated; 
        private DesignSurfaceEventHandler               _designSurfaceDisposed;
        private EventHandler                            _selectionChanged;

        ///  
        /// 
        ///     Creates a new designer application. 
        ///  
        public DesignSurfaceManager() : this(null) {
        } 

        /// 
        /// 
        ///     Creates a new designer application and provides a 
        ///     parent service provider.
        ///  
        public DesignSurfaceManager(IServiceProvider parentProvider) { 
            _parentProvider = parentProvider;
 
            ServiceCreatorCallback callback = new ServiceCreatorCallback(OnCreateService);
            ServiceContainer.AddService(typeof(IDesignerEventService), callback);
        }
 
        /// 
        ///  
        ///     This property should be set by the designer's user interface 
        ///     whenever a designer becomes the active window.  The default
        ///     implementation of this property works with the default 
        ///     implementation of IDesignerEventService to notify interested
        ///     parties that a new designer is now active.  If you provide
        ///     your own implementation of IDesignerEventService you should
        ///     override this property to notify your service appropriately. 
        /// 
        public virtual DesignSurface ActiveDesignSurface { 
            get { 
                IDesignerEventService eventService = EventService;
                if (eventService != null) { 
                    IDesignerHost activeHost = eventService.ActiveDesigner;
                    if (activeHost != null) {
                        return activeHost.GetService(typeof(DesignSurface)) as DesignSurface;
                    } 
                }
 
                return null; 
            }
            set { 
                // If we are providing IDesignerEventService, then we are responsible for
                // notifying it of new designers coming into place.  If we aren't
                // the ones providing the event service, then whoever is providing
                // it will be responsible for updating it when new designers 
                // are created.
                // 
                DesignerEventService eventService = EventService as DesignerEventService; 
                if (eventService != null) {
                    eventService.OnActivateDesigner(value); 
                }
            }
        }
 
        /// 
        ///  
        ///     A collection of design surfaces.  This is offered 
        ///     for convience, and simply maps to IDesignerEventService.
        ///  
        public DesignSurfaceCollection DesignSurfaces {
            get {
                IDesignerEventService eventService = EventService;
                if (eventService != null) { 
                    return new DesignSurfaceCollection(eventService.Designers);
                } 
 
                return new DesignSurfaceCollection(null);
            } 
        }

        /// 
        ///     We access this a lot. 
        /// 
        private IDesignerEventService EventService { 
            get { 
                return GetService(typeof(IDesignerEventService)) as IDesignerEventService;
            } 
        }

        /// 
        ///  
        ///     Provides access to the designer application's
        ///     ServiceContainer. This property allows 
        ///     inheritors to add their own services. 
        /// 
        protected ServiceContainer ServiceContainer { 
            get {
                if (_serviceContainer == null) {
                    _serviceContainer = new ServiceContainer(_parentProvider);
                } 
                return _serviceContainer;
            } 
        } 

        ///  
        /// 
        ///     This event is raised when a new design surface gains
        ///     activation.  This is mapped through IDesignerEventService.
        ///  
        public event ActiveDesignSurfaceChangedEventHandler ActiveDesignSurfaceChanged {
            add { 
                if (_activeDesignSurfaceChanged == null) { 
                    IDesignerEventService eventService = EventService;
                    if (eventService != null) { 
                        eventService.ActiveDesignerChanged += new ActiveDesignerEventHandler(OnActiveDesignerChanged);
                    }
                }
                _activeDesignSurfaceChanged += value; 
            }
            remove { 
                _activeDesignSurfaceChanged -= value; 
                if (_activeDesignSurfaceChanged == null) {
                    IDesignerEventService eventService = EventService; 
                    if (eventService != null) {
                        eventService.ActiveDesignerChanged -= new ActiveDesignerEventHandler(OnActiveDesignerChanged);
                    }
                } 
            }
        } 
 
        /// 
        ///  
        ///     This event is raised when a new design surface is
        ///     created.  This is mapped through IDesignerEventService.
        /// 
        public event DesignSurfaceEventHandler DesignSurfaceCreated { 
            add {
                if (_designSurfaceCreated == null) { 
                    IDesignerEventService eventService = EventService; 
                    if (eventService != null) {
                        eventService.DesignerCreated += new DesignerEventHandler(OnDesignerCreated); 
                    }
                }
                _designSurfaceCreated += value;
            } 
            remove {
                _designSurfaceCreated -= value; 
                if (_designSurfaceCreated == null) { 
                    IDesignerEventService eventService = EventService;
                    if (eventService != null) { 
                        eventService.DesignerCreated -= new DesignerEventHandler(OnDesignerCreated);
                    }
                }
            } 
        }
 
        ///  
        /// 
        ///     This event is raised when a design surface is disposed. 
        ///     This is mapped through IDesignerEventService.
        /// 
        public event DesignSurfaceEventHandler DesignSurfaceDisposed {
            add { 
                if (_designSurfaceDisposed == null) {
                    IDesignerEventService eventService = EventService; 
                    if (eventService != null) { 
                        eventService.DesignerDisposed += new DesignerEventHandler(OnDesignerDisposed);
                    } 
                }
                _designSurfaceDisposed += value;
            }
            remove { 
                _designSurfaceDisposed -= value;
                if (_designSurfaceDisposed == null) { 
                    IDesignerEventService eventService = EventService; 
                    if (eventService != null) {
                        eventService.DesignerDisposed -= new DesignerEventHandler(OnDesignerDisposed); 
                    }
                }
            }
        } 

        ///  
        ///  
        ///     This event is raised when the active designer's
        ///     selection of component set changes.  This is mapped 
        ///     through IDesignerEventService.
        /// 
        public event EventHandler SelectionChanged {
            add { 
                if (_selectionChanged == null) {
                    IDesignerEventService eventService = EventService; 
                    if (eventService != null) { 
                        eventService.SelectionChanged += new EventHandler(OnSelectionChanged);
                    } 
                }
                _selectionChanged += value;
            }
            remove { 
                _selectionChanged -= value;
                if (_selectionChanged == null) { 
                    IDesignerEventService eventService = EventService; 
                    if (eventService != null) {
                        eventService.SelectionChanged -= new EventHandler(OnSelectionChanged); 
                    }
                }
            }
        } 

        ///  
        ///  
        ///     Public method to create a design surface.
        ///  
        public DesignSurface CreateDesignSurface() {

            DesignSurface surface = CreateDesignSurfaceCore(this);
 
            // If we are providing IDesignerEventService, then we are responsible for
            // notifying it of new designers coming into place.  If we aren't 
            // the ones providing the event service, then whoever is providing 
            // it will be responsible for updating it when new designers
            // are created. 
            //
            DesignerEventService eventService = GetService(typeof(IDesignerEventService)) as DesignerEventService;
            if (eventService != null) {
                eventService.OnCreateDesigner(surface); 
            }
 
            return surface; 
        }
 
        /// 
        /// 
        ///     Public method to create a design surface.  This method
        ///     takes an additional service provider.  This service 
        ///     provider will be combined with the service provider
        ///     already contained within DesignSurfaceManager.  Service 
        ///     requests will go to this provider first, and then bubble 
        ///     up to the service provider owned by DesignSurfaceManager.
        ///     This allows for services to be tailored for each design 
        ///     surface.
        /// 
        public DesignSurface CreateDesignSurface(IServiceProvider parentProvider) {
 
            if (parentProvider == null) {
                throw new ArgumentNullException("parentProvider"); 
            } 

            IServiceProvider mergedProvider = new MergedServiceProvider(parentProvider, this); 

            DesignSurface surface = CreateDesignSurfaceCore(mergedProvider);

            // If we are providing IDesignerEventService, then we are responsible for 
            // notifying it of new designers coming into place.  If we aren't
            // the ones providing the event service, then whoever is providing 
            // it will be responsible for updating it when new designers 
            // are created.
            // 
            DesignerEventService eventService = GetService(typeof(IDesignerEventService)) as DesignerEventService;
            if (eventService != null) {
                eventService.OnCreateDesigner(surface);
            } 

            return surface; 
        } 

        ///  
        /// 
        ///     Creates an instance of a design surface.  This can be
        ///     overridden to provide a derived version of DesignSurface.
        ///  
        protected virtual DesignSurface CreateDesignSurfaceCore(IServiceProvider parentProvider) {
            return new DesignSurface(parentProvider); 
        } 

        ///  
        /// 
        ///     Disposes the designer application.
        /// 
        public void Dispose() { 
            Dispose(true);
        } 
 
        /// 
        ///  
        ///     Protected override of Dispose that allows for cleanup.
        /// 
        protected virtual void Dispose(bool disposing) {
            if (disposing && _serviceContainer != null) { 
                _serviceContainer.Dispose();
                _serviceContainer = null; 
            } 
        }
 
        /// 
        /// 
        ///     Retrieves a service in this design surface's service
        ///     container. 
        /// 
        public object GetService(Type serviceType) { 
            if (_serviceContainer != null) { 
                return _serviceContainer.GetService(serviceType);
            } 
            return null;
        }

        ///  
        ///     Private method that demand-creates services we offer.
        ///  
        ///  
        ///     The service container requesting the service.
        ///  
        /// 
        ///     The type of service being requested.
        /// 
        ///  
        ///     A new instance of the service.  It is an error to call this with
        ///     a service type it doesn't know how to create 
        ///  
        private object OnCreateService(IServiceContainer container, Type serviceType) {
 
            if (serviceType == typeof(IDesignerEventService)) {
                return new DesignerEventService();
            }
 
            Debug.Fail("Demand created service not supported: " + serviceType.Name);
            return null; 
        } 

        ///  
        ///     Handles the IDesignerEventService event and relays it to
        ///     DesignSurfaceManager's similar event.
        /// 
        private void OnActiveDesignerChanged(object sender, ActiveDesignerEventArgs e) { 
            Debug.Assert(_activeDesignSurfaceChanged != null, "Should have detached this event handler.");
            if (_activeDesignSurfaceChanged != null) { 
 
                DesignSurface newSurface = null;
                DesignSurface oldSurface = null; 

                if (e.OldDesigner != null) {
                    oldSurface = e.OldDesigner.GetService(typeof(DesignSurface)) as DesignSurface;
                } 

                if (e.NewDesigner != null) { 
                    newSurface = e.NewDesigner.GetService(typeof(DesignSurface)) as DesignSurface; 
                }
 
                _activeDesignSurfaceChanged(this, new ActiveDesignSurfaceChangedEventArgs(oldSurface, newSurface));
            }
        }
 
        /// 
        ///     Handles the IDesignerEventService event and relays it to 
        ///     DesignSurfaceManager's similar event. 
        /// 
        private void OnDesignerCreated(object sender, DesignerEventArgs e) { 
            Debug.Assert(_designSurfaceCreated != null, "Should have detached this event handler.");
            if (_designSurfaceCreated != null) {
                DesignSurface surface = e.Designer.GetService(typeof(DesignSurface)) as DesignSurface;
                if (surface != null) { 
                    _designSurfaceCreated(this, new DesignSurfaceEventArgs(surface));
                } 
            } 
        }
 
        /// 
        ///     Handles the IDesignerEventService event and relays it to
        ///     DesignSurfaceManager's similar event.
        ///  
        private void OnDesignerDisposed(object sender, DesignerEventArgs e) {
            Debug.Assert(_designSurfaceDisposed != null, "Should have detached this event handler."); 
            if (_designSurfaceDisposed != null) { 
                DesignSurface surface = e.Designer.GetService(typeof(DesignSurface)) as DesignSurface;
                if (surface != null) { 
                    _designSurfaceDisposed(this, new DesignSurfaceEventArgs(surface));
                }
            }
        } 

        ///  
        ///     Handles the IDesignerEventService event and relays it to 
        ///     DesignSurfaceManager's similar event.
        ///  
        private void OnSelectionChanged(object sender, EventArgs e) {
            Debug.Assert(_selectionChanged != null, "Should have detached this event handler.");
            if (_selectionChanged != null) {
                _selectionChanged(this, e); 
            }
        } 
 
        /// 
        ///     Simple service provider that merges two providers together. 
        /// 
        private sealed class MergedServiceProvider : IServiceProvider {

            private IServiceProvider _primaryProvider; 
            private IServiceProvider _secondaryProvider;
 
            internal MergedServiceProvider(IServiceProvider primaryProvider, IServiceProvider secondaryProvider) { 
                _primaryProvider = primaryProvider;
                _secondaryProvider = secondaryProvider; 
            }

            object IServiceProvider.GetService(Type serviceType) {
 
                if (serviceType == null) {
                    throw new ArgumentNullException("serviceType"); 
                } 

                object service = _primaryProvider.GetService(serviceType); 

                if (service == null) {
                    service = _secondaryProvider.GetService(serviceType);
                } 

                return service; 
            } 
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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