WPF 中的 Application.DoEvents() 在哪里? [英] Where is the Application.DoEvents() in WPF?

问题描述

我有以下示例代码，每次按下按钮时都会放大:

I have the following sample code that zooms each time a button is pressed:

XAML:

<Window x:Class="WpfApplication12.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">

    <Canvas x:Name="myCanvas">

        <Canvas.LayoutTransform>
            <ScaleTransform x:Name="myScaleTransform" />
        </Canvas.LayoutTransform> 

        <Button Content="Button" 
                Name="myButton" 
                Canvas.Left="50" 
                Canvas.Top="50" 
                Click="myButton_Click" />
    </Canvas>
</Window>

*.cs

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void myButton_Click(object sender, RoutedEventArgs e)
    {
        Console.WriteLine("scale {0}, location: {1}", 
            myScaleTransform.ScaleX,
            myCanvas.PointToScreen(GetMyByttonLocation()));

        myScaleTransform.ScaleX =
            myScaleTransform.ScaleY =
            myScaleTransform.ScaleX + 1;
        
        Console.WriteLine("scale {0}, location: {1}",
            myScaleTransform.ScaleX,
            myCanvas.PointToScreen(GetMyByttonLocation()));
    }
    
    private Point GetMyByttonLocation()
    {
        return new Point(
            Canvas.GetLeft(myButton),
            Canvas.GetTop(myButton));
    }
}

输出为:

scale 1, location: 296;315
scale 2, location: 296;315

scale 2, location: 346;365
scale 3, location: 346;365

scale 3, location: 396;415
scale 4, location: 396;415

正如你所看到的，有一个问题，我想通过使用 Application.DoEvents(); 来解决，但是......它不存在先验.NET 4.

as you can see, there is a problem, that I thought solve by using Application.DoEvents(); but... it does not exist a priori in .NET 4.

怎么办?

推荐答案

WPF 中已弃用旧的 Application.DoEvents() 方法，转而使用 Dispatcher 或 Background Worker Thread 按照您的描述进行处理.请参阅有关如何使用这两个对象的几篇文章的链接.

The old Application.DoEvents() method has been deprecated in WPF in favor of using a Dispatcher or a Background Worker Thread to do the processing as you have described. See the links for a couple of articles on how to use both objects.

如果您绝对必须使用Application.DoEvents()，那么您可以简单地将system.windows.forms.dll 导入您的应用程序并调用该方法.但是，确实不建议这样做，因为您将失去 WPF 提供的所有优势.

If you absolutely must use Application.DoEvents(), then you could simply import the system.windows.forms.dll into your application and call the method. However, this really isn't recommended, since you're losing all the advantages that WPF provides.

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