要显示的列表视图ObservableSelection
问题描述:
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事件代码要显示的列表视图ObservableSelection
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);
答
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;
}
可以显示或指向我一个具体的例子? – DevEx 2012-04-17 20:19:20