AsyncPostBackTrigger.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / Orcas / RTM / ndp / fx / src / xsp / System / Web / Extensions / ui / AsyncPostBackTrigger.cs / 2 / AsyncPostBackTrigger.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.UI { 
    using System; 
    using System.ComponentModel;
    using System.Diagnostics.CodeAnalysis; 
    using System.Globalization;
    using System.Reflection;
    using System.Security.Permissions;
    using System.Web; 
    using System.Web.UI;
    using System.Web.Resources; 
    using System.Web.Util; 

    [ 
    AspNetHostingPermission(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal),
    AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)
    ]
    public class AsyncPostBackTrigger : UpdatePanelControlTrigger { 

        private IScriptManagerInternal _scriptManager; 
 
        private Control _associatedControl;
        private static MethodInfo _eventHandler; 
        private bool _eventHandled;
        private string _eventName;

        public AsyncPostBackTrigger() { 
        }
 
        internal AsyncPostBackTrigger(IScriptManagerInternal scriptManager) { 
            _scriptManager = scriptManager;
        } 

        private static MethodInfo EventHandler {
            get {
                if (_eventHandler == null) { 
                    _eventHandler = typeof(AsyncPostBackTrigger).GetMethod("OnEvent");
                } 
                return _eventHandler; 
            }
        } 

        [
        SuppressMessage("Microsoft.Naming", "CA1706:ShortAcronymsShouldBeUppercase"),
        TypeConverter("System.Web.UI.Design.AsyncPostBackTriggerControlIDConverter, " + 
            AssemblyRef.SystemWebExtensionsDesign)
        ] 
        public new string ControlID { 
            get {
                return base.ControlID; 
            }
            set {
                base.ControlID = value;
            } 
        }
 
        [ 
        DefaultValue(""),
        Category("Behavior"), 
        ResourceDescription("AsyncPostBackTrigger_EventName"),
        TypeConverter("System.Web.UI.Design.AsyncPostBackTriggerEventNameConverter, " +
            AssemblyRef.SystemWebExtensionsDesign),
        ] 
        public string EventName {
            get { 
                if (_eventName == null) { 
                    return String.Empty;
                } 
                return _eventName;
            }
            set {
                _eventName = value; 
            }
        } 
 
        internal IScriptManagerInternal ScriptManager {
            get { 
                if (_scriptManager == null) {
                    Page page = Owner.Page;
                    if (page == null) {
                        throw new InvalidOperationException(AtlasWeb.Common_PageCannotBeNull); 
                    }
                    _scriptManager = UI.ScriptManager.GetCurrent(page); 
                    if (_scriptManager == null) { 
                        throw new InvalidOperationException(String.Format(CultureInfo.InvariantCulture, AtlasWeb.Common_ScriptManagerRequired, Owner.ID));
                    } 
                }
                return _scriptManager;
            }
        } 

        protected internal override void Initialize() { 
            base.Initialize(); 

            _associatedControl = FindTargetControl(true); 

            ScriptManager.RegisterAsyncPostBackControl(_associatedControl);

            string eventName = EventName; 
            if (eventName.Length != 0) {
                // If EventName is specified, attach our event handler to it 
                EventInfo eventInfo = _associatedControl.GetType().GetEvent(eventName, BindingFlags.IgnoreCase | BindingFlags.Instance | BindingFlags.Public); 
                if (eventInfo == null) {
                    throw new InvalidOperationException(String.Format(CultureInfo.InvariantCulture, AtlasWeb.AsyncPostBackTrigger_CannotFindEvent, eventName, ControlID, Owner.ID)); 
                }

                MethodInfo handlerMethod = eventInfo.EventHandlerType.GetMethod("Invoke");
                ParameterInfo[] parameters = handlerMethod.GetParameters(); 
                if (!handlerMethod.ReturnType.Equals(typeof(void)) ||
                    (parameters.Length != 2) || 
                    (typeof(EventArgs).IsAssignableFrom(parameters[1].ParameterType) == false)) { 
                    throw new InvalidOperationException(String.Format(CultureInfo.InvariantCulture, AtlasWeb.AsyncPostBackTrigger_InvalidEvent, eventName, ControlID, Owner.ID));
                } 

                Delegate handler = Delegate.CreateDelegate(eventInfo.EventHandlerType, this, EventHandler);
                eventInfo.AddEventHandler(_associatedControl, handler);
            } 
        }
 
        protected internal override bool HasTriggered() { 
            if (!String.IsNullOrEmpty(EventName)) {
                // If EventName is specified we are triggered if our event was raised 
                return _eventHandled;
            }
            else {
                // If EventName is not specified, check if the control that caused the 
                // postback either has the exact UniqueID we're looking for, or at least
                // begins with it. 
                string sourceElement = ScriptManager.AsyncPostBackSourceElementID; 
                return
                    (sourceElement == _associatedControl.UniqueID) || 
                    (sourceElement.StartsWith(_associatedControl.UniqueID + "$", StringComparison.Ordinal));
            }
        }
 
        // DevDiv Bugs 127369: This method should be private and the reflection lookup should assert reflection permission
        // so the private reflection works in medium trust. 
        // However, ASP.NET AJAX 1.0 was released with this method public. Since it would be a breaking change to make it private 
        // now, it was decided to leave it as is.
        [SuppressMessage("Microsoft.Security", "CA2109:ReviewVisibleEventHandlers", 
            Justification="TODO: This will be fixed in fc_serverfx")]
        public void OnEvent(object sender, EventArgs e) {
            _eventHandled = true;
        } 

        [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")] 
        public override string ToString() { 
            if (String.IsNullOrEmpty(ControlID)) {
                return "AsyncPostBack"; 
            }
            else {
                return "AsyncPostBack: " + ControlID +
                    (String.IsNullOrEmpty(EventName) ? String.Empty : ("." + EventName)); 
            }
        } 
    } 
}

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

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