要显示的列表视图ObservableSelection

Question

我有学生表，课程表和StudentCourse表。在我的WPF上，我正在使用组合框进行“学生”选择。如何使用ObservableCollection？在列表视图中显示相应的课程及其属性（CourseID，CourseName，Credit）。这里是我的组合框SelectionChanged事件代码

private void comboBox1_SelectionChanged(object sender, SelectionChangedEventArgs e) 
    { 
     int MySelect = (int)this.comboBox1.SelectedValue; 
     var SelectedStudent = db.Students.Include("StudentCourses.Course").SingleOrDefault(f => f.StudentID == MySelect); 

Answer 1

如果你还没有，我会强烈推荐使用MVVM风格的方法。你的ListView的ItemsSource应该绑定到你的ViewModel中的ObservableCollection，你的ComboBox的SelectedItem也应该绑定到ViewModel上的一个Propety。当SelectedItem更改并调用属性的setter时，更新ListView绑定的ObservableCollection。

更新：

这里有一个部分实现的解决方案：

XAML：

<DockPanel> 
    <ComboBox ItemsSource="{Binding Students}" SelectedItem="{Binding SelectedComboItem}" DockPanel.Dock="Top"> 
     <ComboBox.ItemTemplate> 
      <DataTemplate> 
       <TextBlock Text="{Binding Name}"/> 
      </DataTemplate> 
     </ComboBox.ItemTemplate> 
    </ComboBox> 

    <ListView ItemsSource="{Binding StudentCourses}"> 
     <ListView.ItemTemplate> 
      <DataTemplate> 
       <StackPanel> 
        <TextBlock Text="{Binding Name, StringFormat={}Name: {0}}"/> 
        <TextBlock Text="{Binding Id, StringFormat={}Id: {0}}"/> 
        <TextBlock Text="{Binding Credit, StringFormat={}Credit: {0}}"/> 
       </StackPanel> 
      </DataTemplate> 
     </ListView.ItemTemplate> 
    </ListView> 
</DockPanel> 

代码：

public class Student 
{ 
    public string Name { get; set; } 
    public List<string> CourseIds { get; set; } 
} 


public class Course 
{ 
    public string Name { get; set; } 
    public string Id { get; set; } 
    public int Credit { get; set; } 
} 


public class ViewModel : INotifyPropertyChanged 
{ 
    public ObservableCollection<Course> StudentCourses { get; set; } 
    public ObservableCollection<Student> Students { get; set; } 


    public Student SelectedComboItem 
    { 
     get { return selectedComboItem_; } 
     set { 
      selectedComboItem_ = value; 
      StudentCourses.Clear(); 
      foreach(Course course in courses_) 
       if(selectedComboItem_.CourseIds.Contains(course.Id)) 
        StudentCourses.Add(course); 
      PropertyChanged(this, new PropertyChangedEventArgs("SelectedComboItem")) ; 
     } 
    } 


    private List<Course> courses_ = new List<Course>(); 
    private Student selectedComboItem_; 


    ... // Read DB and build collections 

    public event PropertyChangedEventHandler PropertyChanged; 
}