当按钮被点击时通知主线程

Question

我想创建一个像这样的弹出窗口

// Create a Popup
var Pop = new Popup() { IsOpen = true };
// Create a StackPanel for the Buttons
var SPanel = new StackPanel() { Background = MainGrid.Background };
// Set the comment
var TxtBlockComment = new TextBlock { Margin = new Thickness(20, 5, 20, 5), Text = Obj.Comment };
// Set the value
var TxtBoxValue = new TextBox { Name = "MeasureValue" };
TxtBoxValue.KeyUp += (sender, e) => { VerifyKeyUp(sender, Measure); };
// Create the button
var ButtonFill = new Button { Content = Loader.GetString("ButtonAccept"), Margin = new Thickness(20, 5, 20, 5), Style = (Style)App.Current.Resources["TextButtonStyle"] };
ButtonFill.Click += (sender, e) => { Obj.Value = TxtBoxValue.Text; };
// Add the items to the StackPanel
SPanel.Children.Add(TxtBlockComment);
SPanel.Children.Add(TxtBoxValue);
SPanel.Children.Add(ButtonFill);
// Set the child on the popup
Pop.Child = SPanel;

我想通知主线程，当ButtonFill.Click事件已经执行，所以我可以继续这个线程

但是我怎么做呢?

Answer 1

我假设您在问如何实现类似于FileOpenPicker.PickSingleFileAsync的对话框行为。您可以使用TaskCompletionSource创建一个可等待任务:

private Task<string> OpenPopupAsync()
{
    var taskSource = new TaskCompletionSource<string>();
    // Create a Popup
    var Pop = new Popup() { IsOpen = true };
    // Create a StackPanel for the Buttons
    var SPanel = new StackPanel() { Background = MainGrid.Background };
    // Set the comment
    var TxtBlockComment = new TextBlock { Margin = new Thickness(20, 5, 20, 5), Text = Obj.Comment };
    // Set the value
    var TxtBoxValue = new TextBox { Name = "MeasureValue" };
    TxtBoxValue.KeyUp += (sender, e) => { VerifyKeyUp(sender, Measure); };
    // Create the button
    var ButtonFill = new Button { Content = Loader.GetString("ButtonAccept"), Margin = new Thickness(20, 5, 20, 5), Style = (Style)App.Current.Resources["TextButtonStyle"] };
    ButtonFill.Click += (sender, e) => { Pop.IsOpen = false; taskSource.SetResult(TxtBoxValue.Text); };
    // Add the items to the StackPanel
    SPanel.Children.Add(TxtBlockComment);
    SPanel.Children.Add(TxtBoxValue);
    SPanel.Children.Add(ButtonFill);
    // Set the child on the popup
    Pop.Child = SPanel;
    return taskSource.Task;
}

简而言之:

• 创建TaskCompletionSource的实例
• 返回Task属性作为可等待任务
• 当您希望调用方法继续时，您可以调用SetResult

在调用方法中，您只需在继续执行之前为方法返回await:

string result = await OpenPopupAsync();
// continue execution after the method returns

我还建议你看看Callisto的Flyout控件，以更简单的方式实现弹出窗口。

Answer 2

为类设置一个布尔属性，并在开始的事件中设置该布尔值为true。

ButtonFill.Click += (sender, e) => { ButtonClicked = true; Obj.Value = TxtBoxValue.Text; };