INotifyPropertyChanged doesn`t update UI(WPF)

Question

问题是 ViewModel 属性与控件属性的绑定无法正常工作。我检查了属性及其值更改，但控件的可见性没有更改。知道这其中涉及什么吗？还是我错过了什么？

视图模型：

class MainViewModel
{
    public LoginViewModel LoginViewModel { get; set; }
    Notifier notifier = new Notifier();
    public MainViewModel()
    {
        LoginViewModel = new LoginViewModel();
    }
    private Visibility mdiPanelVisibility=Visibility.Visible;
    public Visibility MDIPanelVisibility
    {
        get
        {
            return mdiPanelVisibility;
        }
        set
        {
            mdiPanelVisibility = value;
            NotifyPropertyChanged("MDIPanelVisibility");
        }
    }
    private RelayCommand showMDIPanelCommand;
    public RelayCommand ShowMDIPanelCommand
    {
        get
        {
            return showMDIPanelCommand ??
                (showMDIPanelCommand = new RelayCommand(obj =>
                {
                    MDIPanelVisibility = Visibility.Visible;
                }));
        }
    }
    private RelayCommand hideMDIPanelCommand;
    public RelayCommand HideMDIPanelCommand
    {
        get
        {
            return hideMDIPanelCommand ??
                (hideMDIPanelCommand = new RelayCommand(obj =>
                {
                    MDIPanelVisibility = Visibility.Hidden;
                }));
        }
    }
    private event PropertyChangedEventHandler PropertyChanged;
    public void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

和视图：

<Border Visibility="{Binding MDIPanelVisibility}">
        <Border.InputBindings>
            <MouseBinding MouseAction="LeftClick" Command="{Binding HideMDIPanelCommand}"/>
        </Border.InputBindings>
    </Border>
    <ContentPresenter Width="Auto" Grid.RowSpan="2" Panel.ZIndex="1" VerticalAlignment="Center" Visibility="{Binding MDIPanelVisibility}">
        <ContentPresenter.Content>
            <local:MDIView/>
        </ContentPresenter.Content>
    </ContentPresenter>
    <Button Content="Личный кабинет" FontSize="13" Command="{Binding ShowMDIPanelCommand}">
        <Button.Style>
            <Style TargetType="Button" BasedOn="{StaticResource aLogButton}"/>
        </Button.Style>
    </Button> 

Answer 1

MainViewModel类

需要从 INotifyPropertyChanged 继承，而您的类不需要，以便当视图的DataContext设置为MainViewModel实例时，绑定框架的行为符合预期。

更新类定义

public class MainViewModel: INotifyPropertyChanged {
    //...
}