CurrentChangingEventManager.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Base / System / ComponentModel / CurrentChangingEventManager.cs / 1305600 / CurrentChangingEventManager.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: Manager for the CurrentChanging event in the "weak event listener" 
//              pattern.  See WeakEventTable.cs for an overview. 
//
//--------------------------------------------------------------------------- 

using System;
using System.ComponentModel;    // ICollectionView.CurrentChanging
using System.Windows;       // WeakEventManager 

namespace System.ComponentModel 
{ 
    /// 
    /// Manager for the ICollectionView.CurrentChanging event. 
    /// 
    public class CurrentChangingEventManager : WeakEventManager
    {
        #region Constructors 

        // 
        //  Constructors 
        //
 
        private CurrentChangingEventManager()
        {
        }
 
        #endregion Constructors
 
        #region Public Methods 

        // 
        //  Public Methods
        //

        ///  
        /// Add a listener to the given source's event.
        ///  
        public static void AddListener(ICollectionView source, IWeakEventListener listener) 
        {
            if (source == null) 
                throw new ArgumentNullException("source");
            if (listener == null)
                throw new ArgumentNullException("listener");
 
            CurrentManager.ProtectedAddListener(source, listener);
        } 
 
        /// 
        /// Remove a listener to the given source's event. 
        /// 
        public static void RemoveListener(ICollectionView source, IWeakEventListener listener)
        {
            /* for app-compat, allow RemoveListener(null, x) - it's a no-op (see Dev10 796788) 
            if (source == null)
                throw new ArgumentNullException("source"); 
            */ 
            if (listener == null)
                throw new ArgumentNullException("listener"); 

            CurrentManager.ProtectedRemoveListener(source, listener);
        }
 
        #endregion Public Methods
 
        #region Protected Methods 

        // 
        //  Protected Methods
        //

        ///  
        /// Listen to the given source for the event.
        ///  
        protected override void StartListening(object source) 
        {
            ICollectionView typedSource = (ICollectionView)source; 
            typedSource.CurrentChanging += new CurrentChangingEventHandler(OnCurrentChanging);
        }

        ///  
        /// Stop listening to the given source for the event.
        ///  
        protected override void StopListening(object source) 
        {
            ICollectionView typedSource = (ICollectionView)source; 
            typedSource.CurrentChanging -= new CurrentChangingEventHandler(OnCurrentChanging);
        }

        #endregion Protected Methods 

        #region Private Properties 
 
        //
        //  Private Properties 
        //

        // get the event manager for the current thread
        private static CurrentChangingEventManager CurrentManager 
        {
            get 
            { 
                Type managerType = typeof(CurrentChangingEventManager);
                CurrentChangingEventManager manager = (CurrentChangingEventManager)GetCurrentManager(managerType); 

                // at first use, create and register a new manager
                if (manager == null)
                { 
                    manager = new CurrentChangingEventManager();
                    SetCurrentManager(managerType, manager); 
                } 

                return manager; 
            }
        }

        #endregion Private Properties 

        #region Private Methods 
 
        //
        //  Private Methods 
        //

        // event handler for CurrentChanging event
        private void OnCurrentChanging(object sender, CurrentChangingEventArgs args) 
        {
            DeliverEvent(sender, args); 
        } 

        #endregion Private Methods 
    }
}


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

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