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comparison SilverlightValidation/SilverlightValidation.Tests/TestSupport/NotifyPropertyChangedEventWatcher.cs @ 97:1adc1ae981ea

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Tests added to SilverlightValidation.Tests
author stevenhollidge <stevenhollidge@hotmail.com>
date Sat, 05 May 2012 16:39:00 +0100
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96:188f8b366e87 97:1adc1ae981ea
1 using System;
2 using System.Collections.Generic;
3 using System.ComponentModel;
4 using System.Diagnostics;
5 using System.Diagnostics.CodeAnalysis;
6 using System.Globalization;
7 using System.Linq.Expressions;
8
9 namespace SilverlightValidation.Tests.TestSupport
10 {
11 /// <summary>
12 /// A helper class used by NotifyPropertyChangedAssertHelper to monitor PropertyChangedEvent notifications.
13 /// </summary>
14 public class NotifyPropertyChangedEventWatcher : Disposable
15 {
16 private readonly Dictionary<string, int> _raisedCounts = new Dictionary<string, int>();
17
18 // A reference to the instance of the class implementing INotifyPropertyChanged
19 private INotifyPropertyChanged _model;
20
21 /// <summary>
22 /// Initializes a new instance of the <see cref = "NotifyPropertyChangedEventWatcher" /> class.
23 /// </summary>
24 /// <param name = "model">The model.</param>
25 public NotifyPropertyChangedEventWatcher(INotifyPropertyChanged model)
26 {
27 if (model == null) throw new ArgumentNullException("model");
28
29 _model = model;
30 _model.PropertyChanged += OnPropertyChanged;
31 }
32
33 [SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters"),
34 SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
35 public int GetRaisedCount<T>(Expression<Func<T>> propertyExpression)
36 {
37 return GetRaisedCount(PropertySupport.ExtractPropertyName(propertyExpression));
38 }
39
40 public int GetRaisedCount(string propertyName)
41 {
42 propertyName = string.IsNullOrEmpty(propertyName) ? string.Empty : propertyName;
43
44 PropertySupport.VerifyPropertyName(_model, propertyName);
45
46 return _raisedCounts.ContainsKey(propertyName) ? _raisedCounts[propertyName] : 0;
47 }
48
49 private void RecordPropertyChanged(string propertyName)
50 {
51 if (_raisedCounts.ContainsKey(propertyName))
52 {
53 _raisedCounts[propertyName]++;
54 }
55 else
56 {
57 _raisedCounts[propertyName] = 1;
58 }
59 }
60
61 /// <summary>
62 /// The OnPropertyChanged event handler.
63 /// </summary>
64 /// <remarks>
65 /// Records how many times the monitored property name has changed.
66 /// </remarks>
67 private void OnPropertyChanged(object sender, PropertyChangedEventArgs eventArgs)
68 {
69 // If PropertyName is null or string.Empty then it's the 'all properties' changed event.
70 RecordPropertyChanged(string.IsNullOrEmpty(eventArgs.PropertyName) ? string.Empty : eventArgs.PropertyName);
71 }
72
73 /// <summary>
74 /// Releases unmanaged and - optionally - managed resources
75 /// </summary>
76 /// <param name = "disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
77 protected override void Dispose(bool disposing)
78 {
79 if (null != _model)
80 {
81 var model = _model;
82 _model = null;
83 model.PropertyChanged -= OnPropertyChanged;
84 }
85 }
86
87 /// <summary>
88 /// Traces the event counts.
89 /// </summary>
90 [Conditional("DEBUG")]
91 public void TraceEventCounts()
92 {
93 foreach (var pair in _raisedCounts)
94 {
95 string name = string.IsNullOrEmpty(pair.Key) ? "all properties" : pair.Key;
96 int value = pair.Value;
97
98 Debug.WriteLine(string.Format(
99 CultureInfo.InvariantCulture, @"Property '{0}' raised {1} times.", name, value));
100 }
101 }
102 }
103 }