Question

我需要在WPF向导控件上加载叠加层。我正在使用来自wpf extended tooklit的busyIndicator工具。

async await的代码有效但gui线程锁定。当await调用函数

时，我正在尝试添加请等待消息

private async void Button1_Click(object sender, RoutedEventArgs e)
        {
         BusyIndicator.IsBusy = true;
         BusyIndicator.IsEnabled = true;
         BusyIndicator.BusyContent = "Please wait while Site is provisioned";

                            await Task.Run(() =>
                           {
                              LongRunningFunction();
                           });

         BusyIndicator.IsBusy=false;
        }

BusyIndicator的XAML如下所示。

<xctk:BusyIndicator x:Name="BusyIndicator" IsBusy="False"  BusyContent="Please Wait">

</xctk:BusyIndicator>

LonRunningFunction是一个Webservice调用，它不更新UI只返回Bool值

public static bool LongRunningFunction(string URL)
        {

            bool IsPresent = CallWebservice()
           return IsPresent;
        }

问题

1）BusyIndicator似乎在异步调用之前没有触发，而是在LongRunning任务完成时似乎触发了

2）使用async和await时调用gui覆盖的正确过程是什么。

Answer 1

这是我通过异步调用解决问题的方法的上下文：
在这里，我使用MvvM向您展示使用WPF

时的良好做法
using System.Threading; using System.Threading.Tasks; using System.Windows.Data; using System.Windows.Input; using System.Windows.Threading; class VM { Dispatcher _dispatcher = Dispatcher.CurrentDispatcher; //Time consuming operation private void LongTask() { Thread.Sleep(5000); //in here if you need to send something to the UI thread like an event use it like so: _dispatcher.Invoke(new Action(() => { //some code here to invoke an event if (ComponentsLoaded != null) ComponentsLoaded(this, new EventArgs { }); })); } private ICommand _command; //This is the command to be used instead of click event handler public ICommand Command { get { return _command; } private set { _command = value; } } //method associated with ICommand void commandMethod(object parameter) { Busy = true; ThreadPool.QueueUserWorkItem(new WaitCallback(multiThreadTask)); Busy = false; } //the task to be started on another thread void multiThreadTask(object parameter) { LongTask(); } public event EventHandler ComponentsLoaded; }

这是我在WPF中使用多个线程时使用的内容你仍然可以在代码隐藏中使用它来实例化Dispatcher并且你很高兴如果您需要更多信息，请告诉我们。 HTH

使用async await在WPF WizardControl上自定义忙碌覆盖

1 个答案: