当MVVM中的属性更改时，Observable Collection Notify

Question

我正在尝试将可观察集合绑定到DataGrid，我想在数据网格中编辑任何行时发出通知。我的代码可以在添加或删除记录时进行通知，但在编辑记录时不进行通知。请让我知道这是否是在MVVM中使用可观察集合进行绑定的正确方式，以及我是否遗漏了一些内容。提前谢谢。

public class studentViewModel : INotifyPropertyChanged
{
    #region constructor
    public studentViewModel()
    {
        _student = new studentModel();
        myCollection = new ObservableCollection<studentModel>();
        myCollection.Add(_student);
        myCollection.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(myCollection_CollectionChanged);
    }
    void myCollection_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        //throw new NotImplementedException();
        System.Windows.MessageBox.Show(e.Action.ToString());
    }
    #endregion
    #region properties
    studentModel _student;
    ObservableCollection<studentModel> _myCollection;
    public ObservableCollection<studentModel> myCollection
    {
        get { return _myCollection; }
        set
        {
            if (_myCollection != value)
            {
                _myCollection = value;
                raisePropertyChange("myCollection");
            }
        }
    }
    public int rollNo
    {
        get { return _student.rollNo; }
        set
        {
            if (value != _student.rollNo)
            {
                _student.rollNo = value;
                raisePropertyChange("rollNo");
            }
        }
    }
    public string firstName
    {
        get { return _student.firstName; }
        set
        {
            if (value != _student.firstName)
            {
                _student.firstName = value;
                raisePropertyChange("firstName");
            }
        }
    }
    public string lastName
    {
        get { return _student.lastName; }
        set
        {
            if (value != _student.lastName)
            {
                _student.lastName = value;
                raisePropertyChange("lastName");
            }
        }
    }
    #endregion
    #region INotifyPropertyChanged Members
    public event PropertyChangedEventHandler PropertyChanged;

    public void raisePropertyChange(string propertyName)
    {
        if (PropertyChanged != null)
        {
           PropertyChanged(this,new PropertyChangedEventArgs(propertyName));
        }
    }
    #endregion
}
public class studentModel
{
    public int rollNo { get; set; }
    public string firstName { get; set; }
    public string lastName { get; set; }
}

xaml是

<Window.Resources>
    <local:studentViewModel x:Key="StudentsDetails" />
</Window.Resources>
<Grid DataContext="{StaticResource StudentsDetails}">
    <DataGrid ItemsSource="{Binding Path=myCollection, Source={StaticResource StudentsDetails}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
              Name="studentsGrid" CanUserAddRows="True" AutoGenerateColumns="True">
    </DataGrid>
</Grid>

Answer 1

ObservableCollection将在添加或删除记录时通知UI，但在编辑记录时不会通知。由已更改的对象来通知它已更改。

在您的情况下，修改行时，更改的对象类型为studentModel
因此，如果您希望UI在对象更改时得到通知，则还需要在studentModel上实现INotifyPropertyChanged。。

例如

 public class studentModel : INotifyPropertyChanged
   .....