Question

我需要适应我有类似计时器之类的场景，并希望在某个时刻更改UI中反映的属性值（基本上我需要每隔x秒更新一次UI）。

我需要知道如何向ViewModel添加方法并从那里触发PropertyChanged事件。

   namespace MyClient.Common
    {
        public abstract class BindableBase : INotifyPropertyChanged
        {
            public event PropertyChangedEventHandler PropertyChanged;

            protected bool SetProperty<T>(ref T storage, T value, /*[CallerMemberName]*/ String propertyName = null)
            {
                if (object.Equals(storage, value)) return false;

                storage = value;
                this.OnPropertyChanged(propertyName);
                return true;
            }

            protected void OnPropertyChanged(/*[CallerMemberName]*/ string propertyName = null)
            {
                var eventHandler = this.PropertyChanged;
                if (eventHandler != null)
                {
                    eventHandler(this, new PropertyChangedEventArgs(propertyName));
                }
            }

            public void CallOnPropertyChanged()
            {
               // what to add here?
            }

        }
    }

App.xaml.cs

namespace MyClientWPF
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {


        private void DispatcherTimer_Tick(object sender, EventArgs e)
        {
            App._myDataSource.Load();
            App._myDataSource.CallOnPropertyChanged();
            // I need to rise OnPropertyChanged here
        }

        protected override void OnStartup(StartupEventArgs e)
        {


            // timer on the same thread
            System.Windows.Threading.DispatcherTimer dispatcherTimer = new System.Windows.Threading.DispatcherTimer();
            dispatcherTimer.Tick += new EventHandler(DispatcherTimer_Tick);
            dispatcherTimer.Interval = new TimeSpan(0, 0, 20); // 10 seconds
            dispatcherTimer.Start();

            base.OnStartup(e);
        }



    }
}

Answer 1

在你的代码中使用这样的东西吗？

((TestViewModel)this.DataContext).OnPropertyChanged("PropName");

您可以直接致电OnPropertyChanged();。

但似乎必须有一种更好的方式来做你想要完成的事情。我宁愿尝试@emedbo的建议。

如何向ViewModel添加方法并从那里触发PropertyChanged事件？

1 个答案: