source: branches/Async/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Utils/WeakEventManagerBase.cs @ 13401

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
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// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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using System;
using System.Diagnostics;
using System.Windows;

namespace ICSharpCode.AvalonEdit.Utils
{
  /// <summary>
  /// WeakEventManager with AddListener/RemoveListener and CurrentManager implementation.
  /// Helps implementing the WeakEventManager pattern with less code.
  /// </summary>
  public abstract class WeakEventManagerBase<TManager, TEventSource> : WeakEventManager
    where TManager : WeakEventManagerBase<TManager, TEventSource>, new()
    where TEventSource : class
  {
    /// <summary>
    /// Creates a new WeakEventManagerBase instance.
    /// </summary>
    protected WeakEventManagerBase()
    {
      Debug.Assert(GetType() == typeof(TManager));
    }
    
    /// <summary>
    /// Adds a weak event listener.
    /// </summary>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1000:DoNotDeclareStaticMembersOnGenericTypes")]
    public static void AddListener(TEventSource source, IWeakEventListener listener)
    {
      CurrentManager.ProtectedAddListener(source, listener);
    }
    
    /// <summary>
    /// Removes a weak event listener.
    /// </summary>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1000:DoNotDeclareStaticMembersOnGenericTypes")]
    public static void RemoveListener(TEventSource source, IWeakEventListener listener)
    {
      CurrentManager.ProtectedRemoveListener(source, listener);
    }
    
    /// <inheritdoc/>
    protected sealed override void StartListening(object source)
    {
      if (source == null)
        throw new ArgumentNullException("source");
      StartListening((TEventSource)source);
    }
    
    /// <inheritdoc/>
    protected sealed override void StopListening(object source)
    {
      if (source == null)
        throw new ArgumentNullException("source");
      StopListening((TEventSource)source);
    }
    
    /// <summary>
    /// Attaches the event handler.
    /// </summary>
    protected abstract void StartListening(TEventSource source);
    
    /// <summary>
    /// Detaches the event handler.
    /// </summary>
    protected abstract void StopListening(TEventSource source);
    
    /// <summary>
    /// Gets the current manager.
    /// </summary>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1721:PropertyNamesShouldNotMatchGetMethods")]
    protected static TManager CurrentManager {
      get {
        Type managerType = typeof(TManager);
        TManager manager = (TManager)GetCurrentManager(managerType);
        if (manager == null) {
          manager = new TManager();
          SetCurrentManager(managerType, manager);
        }
        return manager;
      }
    }
  }
}