Question

我有一个功能，需要很长时间。

当函数运行时，我想显示一些图片，但这段代码不起作用。为什么？

（我必须只使用框架4 ）

这是代码XAML

<Image Width="33" Stretch="Uniform" Source="{Binding ImagePath, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Grid.Column="0"/>

这是代码

public bool Cmd_TestExe()
 {
Thread trd_A = new Thread(MyThreadTask_ShowImg);
Thread_Status = false;
trd_A.Start();

if (My_Slow_Function(sCon) == false) {
    displayMessage(Status_Failure);}
 }





public void Wait(int sleep) 
{
dynamic dFrame = new DispatcherFrame();

ThreadPool.QueueUserWorkItem(state =>
{
    Thread.Sleep(sleep);
    dFrame.Continue = false;
});
Dispatcher.PushFrame(dFrame);
 }





public void MyThreadTask_ShowImg()
 {
while (Thread_Status == false) {
    Application.Current.Dispatcher.Invoke(new Action(() =>
    {
        if (Second(Now) % (2) == 0) {
            ImagePath = "/Images/exit.png";
            Wait(250);
        } else {
            ImagePath = "/Images/excel.png";
            Wait(250);
            Console.WriteLine(Now);
        }
    }));
}
 }

......这是属性

private string _ImagePath { get; set; }
public string ImagePath {
get { return _ImagePath; }
set {
    _ImagePath = value;
    OnPropertyChanged("ImagePath");
}
 }

Answer 1

首先，你必须在你的Cmd_TestExe方法中返回一个bool。

其次，我从不使用DispatcherFrame，但这就是我要做的：

public partial class MainWindow : Window
{

    Thread myLittleThread;
    bool stop;
    public string ImageSource
    {
        set
        {
            myLittleImage.Source = new BitmapImage(new Uri(value));
        }
    }
    public MainWindow()
    {
        InitializeComponent();
        InitThread();
    }

    private void InitThread()
    {
        myLittleThread = new Thread(DoWork);
        stop = false;
        Application.Current.Exit += MyLittleApplication_Exit;
        myLittleThread.Start();
    }


    private void MyLittleApplication_Exit(object sender,EventArgs e)
    {
        stop = true;
    }

    private void DoWork(){
        string newImageSource;
        while (!stop)
        {
            if (DateTime.Now.Second % 2 == 0)
            {
                newImageSource = "SomeRandomFooImage.png";
            }
            else
            {
                newImageSource = "MyLittleRandomImage.png";
            }

            Application.Current.Dispatcher.Invoke(new Action(() =>
            {
                ImageSource = newImageSource;
            }));

            Thread.Sleep(250);
        }
    }

}

和XAML：

<Image Name="myLittleImage" ></Image>

在函数运行时显示图片的线程

1 个答案: