EventsTab.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / Design / EventsTab.cs / 1 / EventsTab.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Windows.Forms.Design { 
    using System.Runtime.InteropServices; 
    using System.ComponentModel;
    using System.Diagnostics; 
    using System;
    using System.ComponentModel.Design;
    using System.Windows.Forms;
    using System.Windows.Forms.Design; 
    using System.Collections;
    using Microsoft.Win32; 
 

    ///  
    /// 
    ///    Provides a tab on the property browser to display events for selection and linking.
    /// 
    [System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.InheritanceDemand, Name="FullTrust")] 
    [System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.LinkDemand, Name="FullTrust")]
    public class EventsTab : PropertyTab { 
        private IServiceProvider sp; 
        private IDesignerHost currentHost;
        private bool          sunkEvent; 

        /// 
        /// 
        /// Initializes a new instance of the  class. 
        /// 
        public EventsTab(IServiceProvider sp){ 
            this.sp = sp; 
        }
 
        /// 
        /// 
        ///    Gets or sets the name of the tab.
        ///  
        public override string TabName {
            get { 
                return SR.GetString(SR.PBRSToolTipEvents); 
            }
        } 

        /// 
        /// 
        ///    Gets or sets the help keyword for the tab. 
        /// 
        public override string HelpKeyword { 
            get { 
                return "Events"; // do not localize.
            } 
        }

             // override this to reject components you don't want to support.
        ///  
        /// 
        ///    Gets a value indicating whether the specified object can be extended. 
        ///  
        public override bool CanExtend(Object extendee) {
            return !Marshal.IsComObject(extendee); 
        }

        private void OnActiveDesignerChanged(object sender, ActiveDesignerEventArgs adevent){
            currentHost = adevent.NewDesigner; 
        }
 
        ///  
        /// 
        ///    Gets the default property from the specified object. 
        /// 
        public override PropertyDescriptor GetDefaultProperty(object obj) {

            IEventBindingService eventPropertySvc = GetEventPropertyService(obj, null); 

            if (eventPropertySvc == null) { 
                return null; 
            }
 
            // Find the default event.  Note that we rely on GetEventProperties caching
            // the property to event match, so we can == on the default event.
            // We assert that this always works.
            // 
            EventDescriptor defEvent = TypeDescriptor.GetDefaultEvent(obj);
            if (defEvent != null) { 
                return eventPropertySvc.GetEventProperty(defEvent); 
            }
            return null; 
        }

        private IEventBindingService GetEventPropertyService(object obj, ITypeDescriptorContext context) {
 
            IEventBindingService eventPropertySvc = null;
 
            if (!sunkEvent){ 
               IDesignerEventService des = (IDesignerEventService)sp.GetService(typeof(IDesignerEventService));
 
               if (des != null){
                   des.ActiveDesignerChanged += new ActiveDesignerEventHandler(this.OnActiveDesignerChanged);
               }
               sunkEvent = true; 
            }
 
            if (eventPropertySvc == null && currentHost != null) { 
               eventPropertySvc = (IEventBindingService)currentHost.GetService(typeof(IEventBindingService));
            } 

            if (eventPropertySvc == null && obj is IComponent){
                  ISite site = ((IComponent)obj).Site;
 
                  if (site != null) {
                      eventPropertySvc = (IEventBindingService)site.GetService(typeof(IEventBindingService)); 
                  } 
            }
 
            if (eventPropertySvc == null && context != null) {
                eventPropertySvc = (IEventBindingService)context.GetService(typeof(IEventBindingService));
            }
            return eventPropertySvc; 
        }
 
        ///  
        /// 
        ///     Gets all the properties of the tab. 
        /// 
        public override PropertyDescriptorCollection GetProperties(object component, Attribute[] attributes) {
            return GetProperties(null, component, attributes);
        } 

        ///  
        ///  
        ///    Gets the properties of the specified component...
        ///  
        public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object component, Attribute[] attributes) {
            //Debug.Assert(component != null, "Can't get properties for a null item!");

            IEventBindingService eventPropertySvc = GetEventPropertyService(component, context); 

            if (eventPropertySvc == null) { 
                return new PropertyDescriptorCollection(null); 
            }
            EventDescriptorCollection events = TypeDescriptor.GetEvents(component, attributes); 
            PropertyDescriptorCollection realEvents = eventPropertySvc.GetEventProperties(events);


            // Add DesignerSerializationVisibilityAttribute.Content to attributes to see if we have any. 
            Attribute[] attributesPlusNamespace = new Attribute[attributes.Length + 1];
            Array.Copy(attributes, 0, attributesPlusNamespace, 0, attributes.Length); 
            attributesPlusNamespace[attributes.Length] = DesignerSerializationVisibilityAttribute.Content; 

            // If we do, then we traverse them to see if they have any events under the current attributes, 
            // and if so, we'll show them as top-level properties so they can be drilled down into to get events.
            PropertyDescriptorCollection namespaceProperties = TypeDescriptor.GetProperties(component, attributesPlusNamespace);
            if (namespaceProperties.Count > 0) {
                ArrayList list = null; 
                for (int i = 0; i < namespaceProperties.Count; i++) {
                    PropertyDescriptor nsProp = namespaceProperties[i]; 
 
                    TypeConverter tc = nsProp.Converter;
 
                    if (!tc.GetPropertiesSupported()) {
                         continue;
                    }
 
                    Object namespaceValue = nsProp.GetValue(component);
                    EventDescriptorCollection namespaceEvents = TypeDescriptor.GetEvents(namespaceValue, attributes); 
                    if (namespaceEvents.Count > 0) { 
                        if (list == null) {
                            list = new ArrayList(); 
                        }

                        // make this non-mergable
                        // 
                        nsProp = TypeDescriptor.CreateProperty(nsProp.ComponentType, nsProp, MergablePropertyAttribute.No);
                        list.Add(nsProp); 
                    } 
                }
 
                // we've found some, so add them to the event list.
                if (list != null) {
                    PropertyDescriptor[] realNamespaceProperties = new PropertyDescriptor[list.Count];
                    list.CopyTo(realNamespaceProperties, 0); 
                    PropertyDescriptor[] finalEvents = new PropertyDescriptor[realEvents.Count + realNamespaceProperties.Length];
                    realEvents.CopyTo(finalEvents, 0); 
                    Array.Copy(realNamespaceProperties, 0, finalEvents, realEvents.Count, realNamespaceProperties.Length); 
                    realEvents = new PropertyDescriptorCollection(finalEvents);
                } 
            }

            return realEvents;
        } 
    }
} 
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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EventsTab.cs source code in C# .NET

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