我选择的事件没有更新视图，我缺少什么

Question

所有字段在数据框上都标记为twoway，但很明显我有问题。我拥有的页面显示了一个视图，可以在视图的一侧添加新设备，以及另一侧的设备列表。.我要做的是从ListView选择项目时，它将更新值在文本框中查看和编辑目的。

当我创建新设备时，当前的保存选项(下面的代码未显示(当前有效，并将刷新列表。但是，现在完成后，我将返回一个框架。我想做的就是单击"保存"时刷新ListView。

XAML页面的值

<TextBox PlaceholderText="Host Name" Text="{x:Bind ViewModel.HostName, Mode=TwoWay}" Name="hostNameTB" AcceptsReturn="True" />
<TextBox PlaceholderText="Drive Model" Text="{x:Bind ViewModel.DriveModel, Mode=TwoWay}" Name="driveModelTB" />
<TextBox PlaceholderText="Drive SN" Text="{x:Bind ViewModel.DriveSN, Mode=TwoWay}" Name="driveSNTB" AcceptsReturn="True" InputScope="Digits"/>

来自ViewModel的代码

    private Device _ActiveDevice;
    private int _HostName;
    //All Variables Created for DataBinding to XAML page
    //public int HostName { get { return _HostName; } set { _ActiveDevice.HostName = value; } }
    public int HostName { get; set; }
    public string DriveModel { get; set; }
    public string DriveSN { get; set; }
        public override async Task OnNavigatedToAsync(object parameter, NavigationMode mode, IDictionary<string, object> suspensionState)
    {
        Value = (suspensionState.ContainsKey(nameof(Value))) ? suspensionState[nameof(Value)]?.ToString() : parameter?.ToString();
        await Task.CompletedTask;
        var uri = new Uri("http://localhost:2463/api/Devices");
        HttpClient client = new HttpClient();
        try
        {
            var JsonResponse = await client.GetStringAsync(uri);
            var devicesResult = JsonConvert.DeserializeObject<List<Device>>(JsonResponse);
            Devices = devicesResult;
            _ActiveDevice = JsonConvert.DeserializeObject<List<Device>>(JsonResponse)[0];
        }
        catch
        {
            MessageDialog dialog = new MessageDialog("Unable to Access WebService at this Time!");
            await dialog.ShowAsync();
        }
        //client.Dispose();
    }    
    public void deviceList_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        var device = ((sender as ListView).SelectedItem as Device);
        _ActiveDevice = device;
        HostName = device.HostName;
        DriveModel = device.DriveModel;
        DriveSN = device.DriveSN;
    }

Answer 1

您必须从inotifyPropertychanged继承视图模型，以让绑定知道该值的更新。

public class MainViewModel: INotifyPropertyChanged
{
    public int HostName { get => hostName; set { hostName = value; OnPropertyChanged("HostName"); } }
    private int hostName;
    ...
    void OnPropertyChanged(String prop)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(prop));
    }
    public event PropertyChangedEventHandler PropertyChanged;
}

将您的绑定(以及其他所有绑定(更新：

<TextBox PlaceholderText="Host Name" Text="{Binding ViewModel.HostName, UpdateSourceTrigger=PropertyChanged}" Name="hostNameTB" AcceptsReturn="True" />

Answer 2

我已经离开了..我的修复程序更多是鲁福爵士提出的。然后确保所选的设备已更新每个属性。

private int _HostName;
public int HostName { get { return _HostName; } set { Set(ref _HostName, value); } }
public void deviceList_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        var device = ((sender as ListView).SelectedItem as Device);
        //_ActiveDevice = device;
        HostName = device.HostName;
        DriveModel = device.DriveModel;
        DriveSN = device.DriveSN;