小编D. *_*hov的帖子

我对 DatePicker 的 Binding nullable 属性有问题。我第一次运行我的应用程序时我有什么， 但是当我将日期设置为从今天到 7 天后它工作正常时。如果我在一周后选择日期，则属性设置为 null。 一周后

public class Pledge
{
    public int ID { get; set; }
    public string ClientName { get; set; }
    public string Passport { get; set; }
    public string IssuedBy { get; set; }
    [Column(TypeName = "Date")]
    public DateTime? Birthday { get; set; }
    [Column(TypeName = "Date")]
    public DateTime? IssuedDate { get; set; }
    public string Registration { get; set; }
    public string Phone { get; set; }
    public …

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的变化,但控件的可见性不会改变.知道这涉及到什么吗？或者我错过了什么？

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 …