UWP C# - 为什么 NotifyPropertyChanged 在这种情况下不触发？

Question

在以下情况下，NotifyPropertyChanged 不会触发，因此我的 UI 不会更新（显示的简化视图模型）：

public class NetworkGraphViewModel : INotifyPropertyChanged
{

     private String byteSentSpeed { get; set; }

     public String ByteSentSpeed { get { return byteSentSpeed; } set { byteSentSpeed = value; NotifyPropertyChanged("ByteSentSpeed"); } }

     private void MyEvent(object sender, object eventArgs)
     {
         byteSentSpeed = byteSentSpeed + 5;
     }

     public void NotifyPropertyChanged(string propertyName)
     {
         if (PropertyChanged != null)
             PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
     }

}

XAML:


<TextBlock Margin="30,5,10,5"  Grid.Column="1" Grid.Row="2" x:Name="bytesSentSpeedBlock" Text="{Binding ByteSentSpeed}"/>

...而以下示例会更新 UI:

public class NetworkGraphViewModel : INotifyPropertyChanged
{

     private String byteSentSpeed { get; set; }

     public String ByteSentSpeed { get { return byteSentSpeed; } set { byteSentSpeed = value; NotifyPropertyChanged("ByteSentSpeed"); } }

     private void MyEvent(object sender, object eventArgs)
     {
         byteSentSpeed = byteSentSpeed + 5;
         NotifyPropertyChanged("ByteSentSpeed")
     }

     public void NotifyPropertyChanged(string propertyName)
     {
         if (PropertyChanged != null)
             PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
     }

}

XAML:


<TextBlock Margin="30,5,10,5"  Grid.Column="1" Grid.Row="2" x:Name="bytesSentSpeedBlock" Text="{Binding ByteSentSpeed}"/>

也许我错误地假设更改会通过分配给 "byteSentSpeed" 的值传播到 public 变量 "ByteSentSpeed"?

这真的是最有效的方法吗，还是我在做一些愚蠢的事情？

Answer 1

byteSentSpeed 和 ByteSentSpeed 是两个不同的属性。设置前者不会调用引发 PropertyChanged 事件的后者的 setter。

并且byteSentSpeed应该是支持字段而不是属性:

 private String byteSentSpeed;
 public String ByteSentSpeed { get { return byteSentSpeed; } set { byteSentSpeed = value; NotifyPropertyChanged("ByteSentSpeed"); } }

只要您想更新 UI:

，您应该设置属性

private void MyEvent(object sender, object eventArgs)
{
    ByteSentSpeed = ByteSentSpeed + 5;
}

UWP C# - 为什么 NotifyPropertyChanged 在这种情况下不触发？

UWP C# - Why does NotifyPropertyChanged not fire in this scenario?

c#

mvvm

uwp

getter-setter

inotifypropertychanged