INotifyPropertyChanged將不會更新視圖

Question

我已經做過很多次了，但這讓我很困惑。

    public class ObservableObject : System.ComponentModel.INotifyPropertyChanged
    {
        public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;
        public void NotifyPropertyChanged(Object PropertyValue)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(PropertyValue.ToString()));
            }
        }
    }

簡單通知屬性已更改。

非常非常簡單的自定義類對象

class Device : ObservableObject
{
    public String DeviceName
    {
        get { return _DeviceName; }
        set { _DeviceName = value; NotifyPropertyChanged("DeviceName"); }
    }
    private String _DeviceName = "";

    public Device() { }
    public Device(String ComputerName)
    {
        DeviceName = ComputerName;
    }
}

視圖模型

class MainWindowViewModel :ObservableObject
{
    public Device SelectedDevice { get; set; }
    public List<Device> DeviceList
    {
        get { return _DeviceList; }
        set { _DeviceList = value; NotifyPropertyChanged("DeviceList"); }
    }
    public List<Device> _DeviceList = new List<Device>();
    public MainWindowViewModel()
    {
        CreateDelegateCommands();
        DeviceList.Add(new Device("Metabox-PC"));
        DeviceList.Add(new Device("NewPC"));
        DeviceList.Add(new Device("OldPC"));
    }
    #region Delegated Commands
    public Boolean CreateDelegateCommands()
    {
        try
        {
            ContextMenuCommand = new DelegateCommand(DelegatedContextMenuCommand);
            return true;
        }
        catch
        {
            return false;
        }
    }
    public DelegateCommand ContextMenuCommand { get; set; }

    public void DelegatedContextMenuCommand(Object Parameter)
    {
        System.Windows.Controls.MenuItem MenuItemClicked = Parameter as System.Windows.Controls.MenuItem;
        switch (MenuItemClicked.Header.ToString())
        {
            case "Delete": { DeviceList.Remove(SelectedDevice); NotifyPropertyChanged("DeviceList"); break; }
        }
    }
    #endregion
}

視圖

 <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="102*"/>
            <ColumnDefinition Width="415*"/>
        </Grid.ColumnDefinitions>
        <ListView ItemsSource="{Binding DeviceList}" SelectedItem="{Binding SelectedDevice,Mode=TwoWay}">
            <ListView.ContextMenu>
                <ContextMenu>
                    <MenuItem Header="Delete" Command="{Binding ContextMenuCommand}" CommandParameter="{Binding RelativeSource={RelativeSource Self}}"/>
                </ContextMenu>
            </ListView.ContextMenu>
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="Device" DisplayMemberBinding="{Binding DeviceName}"/>
                </GridView>
            </ListView.View>
        </ListView>

    </Grid>

簡而言之，您右鍵單擊我放入List<T>的測試對象之一，然后單擊“刪除”。 這項工作並觸發委托的命令，然后該命令會處理正常，並處理NotifyPropertyChanged（T）觸發器。 沒有任何錯誤，但是我的視圖仍然顯示相同的三個對象。 但是在視圖模型中， List<T>僅顯示2個對象。

我哪里出問題了？

Answer 1

我認為你應該嘗試

  public ObservableCollection<Device> DeviceList
    {
        get { return _DeviceList; }
        set { _DeviceList = value; NotifyPropertyChanged("DeviceList"); }
    }
    public ObservableCollection<Device> _DeviceList = new ObservableCollection<Device>();