如何在 MouseLeftButtonDown 事件中两次更改按钮的背景图像？

Question

我在 MainWindow.xaml.cs 中编写了以下事件处理程序。我想实现这样的效果，当业务逻辑为运行时，runbutton的背景图切换为powerOnOff1.png，当业务逻辑结束时，背景图切换回powerOnOff0.png。

    private void Run_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
            {
                //set run button background image to powerOnOff1.png indicates business logic is going to run.
                BitmapImage ima0 = new BitmapImage(new Uri("picture/powerOnOff1.png", UriKind.Relative));             
                image.Source = ima0;

                //business logic
                ...... 

                //restore Runbutton background image to powerOnOff0.png indicates business logic is finished.
                BitmapImage ima1 = new BitmapImage(new Uri("picture/powerOnOff0.png", UriKind.Relative));
                image.Source = ima1;  
            }

以上代码无效。它总是显示 powerOnOff0.png 背景图片。它需要多线程吗？

Answer 1

Does it require multithreading?

是的。您需要在后台线程上执行业务逻辑。最简单的方法是启动一个新任务并等待它：

private async void Run_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    //set run button background image to powerOnOff1.png indicates business logic is going to run.
    image.Source = new BitmapImage(new Uri("picture/powerOnOff1.png", UriKind.Relative));

    await Task.Run(() =>
    {
        //business logic here
    });

    //restore Runbutton background image to powerOnOff0.png indicates business logic is finished.
    image.Source = new BitmapImage(new Uri("picture/powerOnOff0.png", UriKind.Relative));
}

如何在 MouseLeftButtonDown 事件中两次更改按钮的背景图像？

How can I change the button's background image twice in MouseLeftButtonDown event?

wpf

button

background-image

mouseleftbuttondown