public class Person{public string Name { get; set; }public int Age { get; set; }}

public class PersonDataHelper{public static ObservableCollection<Person> GetPersons(){ObservableCollection<Person> samplePersons = new ObservableCollection<Person>();samplePersons.Add(new Person() {Name = "张三", Age = 33});samplePersons.Add(new Person() { Name ="王五", Age= 22 });samplePersons.Add(new Person() { Name = "李四", Age = 35 });samplePersons.Add(new Person() { Name = "LearningHard", Age = 27 });return samplePersons;}}

public class QueryCommand :ICommand{#region Fieldsprivate Action _execute;private Func<bool> _canExecute;#endregion public QueryCommand(Action execute): this(execute, null){ }public QueryCommand(Action execute, Func<bool> canExecute){if (execute == null)throw new ArgumentNullException("execute");_execute = execute;_canExecute = canExecute;}#region ICommand Memberpublic event EventHandler CanExecuteChanged{add{if (_canExecute != null){CommandManager.RequerySuggested += value;}}remove{if (_canExecute != null){CommandManager.RequerySuggested -= value;}}}public bool CanExecute(object parameter){return _canExecute == null ? true : _canExecute();}public void Execute(object parameter){_execute();}#endregion}

 1 public class PersonListViewModel : INotifyPropertyChanged
 2     {
 3         #region Fields
 4         private string _searchText;
 5         private ObservableCollection<Person> _resultList;
 6         #endregion
 7
 8         #region Properties
 9
10         public ObservableCollection<Person> PersonList { get; private set; }
11
12         // 查询关键字
13         public string SearchText
14         {
15             get { return _searchText; }
16             set
17             {
18                 _searchText = value;
19                 RaisePropertyChanged("SearchText");
20             }
21         }
22
23         // 查询结果
24         public ObservableCollection<Person> ResultList
25         {
26             get { return _resultList; }
27             set
28             {
29                 _resultList = value;
30                 RaisePropertyChanged("ResultList");
31             }
32         }
33
34         public ICommand QueryCommand
35         {
36             get { return new QueryCommand(Searching, CanSearching); }
37         }
38
39         #endregion
40
41         #region Construction
42         public PersonListViewModel()
43         {
44             PersonList = PersonDataHelper.GetPersons();
45             _resultList = PersonList;
46         }
47
48         #endregion
49
50         #region Command Handler
51         public void Searching()
52         {
53             ObservableCollection<Person> personList = null;
54             if (string.IsNullOrWhiteSpace(SearchText))
55             {
56                 ResultList = PersonList;
57             }
58             else
59             {
60                 personList = new ObservableCollection<Person>();
61                 foreach (Person p in PersonList)
62                 {
63                     if (p.Name.Contains(SearchText))
64                     {
65                         personList.Add(p);
66                     }
67                 }
68                 if (personList != null)
69                 {
70                     ResultList = personList;
71                 }
72             }
73         }
74
75         public bool CanSearching()
76         {
77             return true;
78         }
79
80         #endregion
81
82         #region INotifyPropertyChanged Members
83
84         public event PropertyChangedEventHandler PropertyChanged;
85
86         #endregion
87
88         #region Methods
89         private void RaisePropertyChanged(string propertyName)
90         {
91             // take a copy to prevent thread issues
92             PropertyChangedEventHandler handler = PropertyChanged;
93             if (handler != null)
94             {
95                 handler(this, new PropertyChangedEventArgs(propertyName));
96             }
97         }
98         #endregion
99     }

<Window x:Class="MVVMDemo.View.PersonsView"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:local="clr-namespace:MVVMDemo.ViewModel"Title="PersonsView" Height="350" Width="400"><!--设置DataContex是ViewModel类，当然你也可以使用后台代码设置--><Window.DataContext><local:PersonListViewModel /></Window.DataContext><Grid><Grid.RowDefinitions><RowDefinition Height="50"/><RowDefinition Height="*"/></Grid.RowDefinitions><TextBox Grid.Row="0" Name="searchtxt" Text="{Binding  Path=SearchText, Mode=TwoWay}" HorizontalAlignment="Left" Height="30" Width="280" Margin="10,0,0,0"></TextBox><Button Grid.Row="0" Name="searchBtn" Content="Search" Command="{Binding Path=QueryCommand}" Width="80" Height="30" HorizontalAlignment="Right" Margin="0,0,10,0"></Button><DataGrid Grid.Row="1" Name="datGrid" HorizontalAlignment="Center"VerticalAlignment="Top" ItemsSource="{Binding Path=ResultList}" Width="300"></DataGrid></Grid>
</Window>