c#中不允许异步属性并没有技术上的原因。这是一个有目的的设计决策，因为“异步属性”是一个矛盾的说法。

属性应该返回当前值;他们不应该开始幕后行动。

通常，当有人想要一个“异步属性”时，他们真正想要的是以下内容之一:

An asynchronous method that returns a value. In this case, change the property to an async method. A value that can be used in data-binding but must be calculated/retrieved asynchronously. In this case, either use an async factory method for the containing object or use an async InitAsync() method. The data-bound value will be default(T) until the value is calculated/retrieved. A value that is expensive to create, but should be cached for future use. In this case, use AsyncLazy from my blog or AsyncEx library. This will give you an awaitable property.

更新:我在最近的一篇“异步面向对象”博客文章中介绍了异步属性。

c#中不允许异步属性并没有技术上的原因。这是一个有目的的设计决策，因为“异步属性”是一个矛盾的说法。

属性应该返回当前值;他们不应该开始幕后行动。

通常，当有人想要一个“异步属性”时，他们真正想要的是以下内容之一:

An asynchronous method that returns a value. In this case, change the property to an async method. A value that can be used in data-binding but must be calculated/retrieved asynchronously. In this case, either use an async factory method for the containing object or use an async InitAsync() method. The data-bound value will be default(T) until the value is calculated/retrieved. A value that is expensive to create, but should be cached for future use. In this case, use AsyncLazy from my blog or AsyncEx library. This will give you an awaitable property.

更新:我在最近的一篇“异步面向对象”博客文章中介绍了异步属性。

由于我的解耦架构，我确实需要调用源自get方法。所以我想到了下面的实现。

用法:标题在ViewModel或一个对象中，你可以静态地声明为页面资源。绑定到它，当getTitle()返回时，值将在不阻塞UI的情况下填充。

string _Title;
public string Title
{
    get
    {
        if (_Title == null)
        {   
            Deployment.Current.Dispatcher.InvokeAsync(async () => { Title = await getTitle(); });
        }
        return _Title;
    }
    set
    {
        if (value != _Title)
        {
            _Title = value;
            RaisePropertyChanged("Title");
        }
    }
}

你可以像这样使用Task:

public int SelectedTab
        {
            get => selected_tab;
            set
            {
                selected_tab = value;

                new Task(async () =>
                {
                    await newTab.ScaleTo(0.8);
                }).Start();
            }
        }

我认为.GetAwaiter().GetResult()正是这个问题的解决方案，不是吗? 例如:

string _Title;
public string Title
{
    get
    {
        if (_Title == null)
        {   
            _Title = getTitle().GetAwaiter().GetResult();
        }
        return _Title;
    }
    set
    {
        if (value != _Title)
        {
            _Title = value;
            RaisePropertyChanged("Title");
        }
    }
}

Necromancing。 在。net Core/NetStandard2中，你可以使用Nito.AsyncEx.AsyncContext.Run来代替System.Windows.Threading.Dispatcher.InvokeAsync:

class AsyncPropertyTest
{

    private static async System.Threading.Tasks.Task<int> GetInt(string text)
    {
        await System.Threading.Tasks.Task.Delay(2000);
        System.Threading.Thread.Sleep(2000);
        return int.Parse(text);
    }


    public static int MyProperty
    {
        get
        {
            int x = 0;

            // https://stackoverflow.com/questions/6602244/how-to-call-an-async-method-from-a-getter-or-setter
            // https://stackoverflow.com/questions/41748335/net-dispatcher-for-net-core
            // https://github.com/StephenCleary/AsyncEx
            Nito.AsyncEx.AsyncContext.Run(async delegate ()
            {
                x = await GetInt("123");
            });

            return x;
        }
    }


    public static void Test()
    {
        System.Console.WriteLine(System.DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss.fff"));
        System.Console.WriteLine(MyProperty);
        System.Console.WriteLine(System.DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss.fff"));
    }


}

如果你只是选择System.Threading.Tasks.Task. run或System.Threading.Tasks.Task<int>。跑吧，那就没用了。