PropertyChangedEventHandler 不会异步触发 [英] PropertyChangedEventHandler not firing asynchronically

问题描述

我已经实现了这个属性来隐藏和显示一个元素:

I've implemented this property to hide and show an element:

private bool isWorking = false;

public bool IsWorking {
    get {
        return this.isWorking;
    }

    set {
        this.isWorking = value;
        OnPropertyChanged("IsWorking");
    }
}

public event PropertyChangedEventHandler PropertyChanged;

protected void OnPropertyChanged(string name)
{
    PropertyChangedEventHandler handler = PropertyChanged;
    if (handler != null)
    {
        handler(this, new PropertyChangedEventArgs(name));
    }
}

但是当我更改属性时，即使该方法是异步的，它也会以同步方式更改.

But when i change the property, even if the method is async, it's changing in a sync way.

你能解释一下如何解决这个问题吗?我试图在已更改的属性或代码中移动调度程序事件，但它不起作用！

Can you explain me how to solve the issue? I tried to move a dispatcher event inside the property changed or the code, but it doesn't work!

推荐答案

你可能想要一个 async Click 事件处理程序，如下所示:

You probably want to have an async Click event handler like this:

private async void Button_Click(object sender, RoutedEventArgs e)
{
    viewModel.IsWorking = true;

    await Task.Run(() =>
    {
       // do some long processing
    });

    viewModel.IsWorking = false;
}

<小时>

或者视图模型中的异步方法

---

Or an async method in your view model

public async Task DoSomeProcessing()
{
    IsWorking = true;

    await Task.Run(() =>
    {
       // do some long processing
    });

    IsWorking = false;
}

从异步点击处理程序调用，如

that is called from an async Click handler like

private async void Button_Click(object sender, RoutedEventArgs e)
{
    await viewModel.DoSomeProcessing();
}

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