我有材料設計對話框：<materialDesign:DialogHost CloseOnClickAway="True" IsOpen="{Binding IsOpenDialogAddingEP, UpdateSourceTrigger=PropertyChanged}">...</materialDesign:DialogHost><Button Command="{Binding CloseDialogAddingEPCommand}"/>我想在單擊按鈕時關閉對話框，在代碼后面：public ICommand CloseDialogAddingEPCommand { get; private set; }public MyPage(){    InitializeComponent();    DataContext = this;    CloseDialogAddingEPCommand = new RelayCommand(CloseDialogAddingEP);}void CloseDialogAddingEP(){     IsOpenDialogAddingEP = false;}private bool isOpenDialogAddingEP;public bool IsOpenDialogAddingEP{   get { return isOpenDialogAddingEP; }   set   {        isOpenDialogAddingEP = value;        OnPropertyChanged("IsOpenDialogAddingEP");    }}public event PropertyChangedEventHandler PropertyChanged;protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null){            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));}但按鈕沒有任何作用，你能告訴我為什么嗎？