我的组合框选定的值绑定不会以双向方式回流数据绑定

Question

使用简单MVVM框架创建简单的Silverlight 4.0 LOB应用程序。

我有一个雇员列表视图，显示列表中的所有员工，我有我的EmployeeListViewModel一些特性如下：

private Grade selectedGrade; 
    public Grade SelectedGrade 
    { 
     get { return selectedGrade; } 
     set 
     { 
      selectedGrade = value; 
      NotifyPropertyChanged(m => m.SelectedGrade); 
     } 
    } 

    private Religion selectedReligion; 
    public Religion SelectedReligion 
    { 
     get { return selectedReligion; } 
     set 
     { 
      selectedReligion = value; 
      NotifyPropertyChanged(m => m.SelectedReligion); 
     } 
    } 
    private ObservableCollection<Grade> grades; 
    public ObservableCollection<Grade> Grades 
    { 
     get { return grades; } 
     set 
     { 
      grades = value; 
      NotifyPropertyChanged(m => m.Grades); 
     } 
    } 

    private ObservableCollection<Religion> religions; 
    public ObservableCollection<Religion> Religions 
    { 
     get { return religions; } 
     set 
     { 
      religions = value; 
      NotifyPropertyChanged(m => m.Religions); 
     } 
    } 
    private ObservableCollection<Department> departments; 
    public ObservableCollection<Department> Departments 
    { 
     get { return departments; } 
     set 
     { 
      departments = value; 
      NotifyPropertyChanged(m => m.Departments); 
     } 
    } 
    private Employee selectedEmployee; 
    public Employee SelectedEmployee 
    { 
     get { return selectedEmployee; } 
     set 
     { 
      selectedEmployee = value; 
      SetCanProperties(); 
      NotifyPropertyChanged(m => m.SelectedEmployee); 
     } 
    } 
    private ObservableCollection<Employee> employees; 
    public ObservableCollection<Employee> Employees 
    { 
     get { return employees; } 
     set 
     { 
      employees = value; 
      NotifyPropertyChanged(m => m.Employees); 
     } 
    } 
    private Department selectedDepartment; 
    public Department SelectedDepartment 
    { 
     get { return selectedDepartment; } 
     set 
     { 
      selectedDepartment = value; 
      NotifyPropertyChanged(m => m.SelectedDepartment); 
     } 
    } 

现在在我看来，我有一个按钮，在我的员工来编辑选定员工它开创了一个新的子窗口与EmployeeDetails编辑

EmployeeListViewModel viewModel; 
    public EmployeeListView() 
    { 
     InitializeComponent(); 
     viewModel = (EmployeeListViewModel)DataContext; 
    } 

这里列出的是编辑员工方法

private void editItemButton_Click(object sender, RoutedEventArgs e) 
    { 
     // Exit if no product selected 
     if (viewModel.SelectedEmployee == null) return; 

     // Create a product detail model 
     EmployeeDetailViewModel detailModel = 
      new EmployeeDetailViewModel(viewModel.SelectedEmployee); 
     // set comboboxes !! 

     detailModel.Departments = viewModel.Departments; 
     detailModel.Religions = viewModel.Religions; 

     detailModel.Grades = viewModel.Grades; 

     // Start editing 
     detailModel.BeginEdit(); 

     // Show EmployeeDetail view 
     EmployeeDetailView itemDetail = new EmployeeDetailView(detailModel); 
     itemDetail.Closed += (s, ea) => 
     { 
      if (itemDetail.DialogResult == true) 
      { 
       // Confirm changes 

       detailModel.EndEdit(); 
      } 
      else 
      { 
       // Reject changes 
       detailModel.CancelEdit(); 
      } 
     }; 
     itemDetail.Show(); 
    } 

现在

我的详细信息子视图我有这个Constractor

public EmployeeDetailView(EmployeeDetailViewModel viewModel) 
    { 
     InitializeComponent(); 
     DataContext = viewModel; 
    } 

，这里是我的DetailsViewModel constractor

public EmployeeDetailViewModel(Employee model) 
    { 
     base.Model = model; 
    } 
     private ObservableCollection<Religion> religions; 
    public ObservableCollection<Religion> Religions 
    { 
     get { return religions; } 
     set 
     { 
      religions = value; 
      NotifyPropertyChanged(m => m.Religions); 
     } 
    } 

    private ObservableCollection<Grade> grades; 
    public ObservableCollection<Grade> Grades 
    { 
     get { return grades; } 
     set 
     { 
      grades = value; 
      NotifyPropertyChanged(m => m.Grades); 
     } 
    } 
    private ObservableCollection<Department> departments; 
    public ObservableCollection<Department> Departments 
    { 
     get { return departments; } 
     set 
     { 
      departments = value; 
      NotifyPropertyChanged(m => m.Departments); 
     } 
    } 

毕竟这现在来结合我有三个组合框 的部门，宗教和等级（这是我员工表中的外键）

<ComboBox ItemsSource="{Binding Departments}" DisplayMemberPath="DepartmentName" SelectedValue="{Binding Model.Emp_Department, Mode=TwoWay}" SelectedValuePath="DepartmentId"/> 
    <ComboBox ItemsSource="{Binding Grades}" DisplayMemberPath="GradeName" SelectedValue="{Binding Model.Emp_Grade, Mode=TwoWay}" SelectedValuePath="GradeId"/> 

等等..问题是，只有部门组合框正在更新源值，当我更改它的值

和其他组合框不..即使绑定语句完全相同！

很抱歉写这么多..但任何人都可以帮助我吗？

非常感谢

Answer 1

很遗憾，您MVVM分离是有点搞砸了，你是从直接查看到底层模型（意味着视图模型的任何业务逻辑/确认）结合被绕过。

但是，你似乎一切准备就绪，所以我会建议如下：

更改您的XAML到这个（注意，从的SelectedValue到的SelectedItem的变化）：二传手内

<ComboBox ItemsSource="{Binding Departments}" DisplayMemberPath="DepartmentName" SelectedItem="{Binding SelectedDepartment, Mode=TwoWay}"/> 
<ComboBox ItemsSource="{Binding Grades}" DisplayMemberPath="GradeName" SelectedItem="{Binding SelectedGrade, Mode=TwoWay}"/> 

然后SelectedDepartment/SelectedGrade属性中，执行任何必需的验证，然后将所选项目的ID写入（detail）模型中的属性。

希望它有帮助。

Answer 2

那么这里是我做我的连击：

<ComboBox ItemsSource="{Binding Path=ListPeople, UpdateSourceTrigger= PropertyChanged}" SelectedItem="{Binding Path=SelectedPerson, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" DisplayMemberPath="FirstName"/> 

，并在我的视图模型：

private ObservableCollection<Person> listPeople = new ObservableCollection<Person>(); 

public IEnumerable<Person> ListPeople 
    { 
     get { return this.listPeople; } 
    } 

public Person SelectedPerson 
    { 
     get { return selectedPerson; } 
     set 
     { 
      selectedPerson = value; 
      if (selectedPerson != null) 
      { 
       NextToPayID = selectedPerson.PersonID; 
      } 
      base.RaisePropertyChanged("SelectedPerson"); 
     } 
    } 

看到，如果你可以用它来帮助！