我正在通过Revit建筑模型软件的API创建一个自定义添加命令。由于我的命令可能需要一些时间才能完成,因此我希望在它工作时向用户显示带有进度条的窗口。
通常,如果我要创建这样的进度窗口,它将位于主UI线程上,而实际的工作将在辅助工作线程上进行。然而,Revit要求任何对API的访问都必须通过调用自定义命令的线程进行。因此,我必须在第二个线程上创建我的进度条。
我找到了这篇关于如何在单独的线程中启动WPF窗口的博客文章,并以此为基础来解决问题。以下是我的自定义命令类。
public class SampleProgressWindowCommand : Autodesk.Revit.UI.IExternalCommand
{
private ProgressWindow progWindow;
internal static EventWaitHandle _progressWindowWaitHandle;
public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
{
//Starts New Progress Window Thread
using (_progressWindowWaitHandle = new AutoResetEvent(false))
{
//Starts the progress window thread
Thread newprogWindowThread = new Thread(new ThreadStart(ShowProgWindow));
newprogWindowThread.SetApartmentState(ApartmentState.STA);
newprogWindowThread.IsBackground = true;
newprogWindowThread.Start();
//Wait for thread to notify that it has created the window
_progressWindowWaitHandle.WaitOne();
}
//Does some work that takes a long time
for (int i = 1; i <= 100; i++)
{
//Updates Progress
this.progWindow.UpdateProgress("Item " + i.ToString(), i, 100);
//Does some fake work
System.Threading.Thread.Sleep(700);
}
//closes the Progress window
progWindow.Dispatcher.Invoke(new Action(progWindow.Close));
//Show Result to User
Autodesk.Revit.UI.TaskDialog.Show("Task", "Task Completed");
return Result.Succeeded;
}
private void ShowProgWindow()
{
//creates and shows the progress window
progWindow = new ProgressWindow();
progWindow.Show();
//makes sure dispatcher is shut down when the window is closed
progWindow.Closed +=new EventHandler(progWindow_Closed);
//Notifies command thread the window has been created
_progressWindowWaitHandle.Set();
//Starts window dispatcher
System.Windows.Threading.Dispatcher.Run();
}
}
这里是我的ProgressWindow类中的UpdateProgress()方法
public void UpdateProgress(string message, int current, int total)
{
this.Dispatcher.Invoke(new Action<string, int, int>(
delegate(string m, int v, int t)
{
this.progressBar1.Maximum = System.Convert.ToDouble(t);
this.progressBar1.Value = System.Convert.ToDouble(v);
this.messageLbl.Content = m;
}),
System.Windows.Threading.DispatcherPriority.Background,
message, current, total);
}
我的第一个问题是,总体上我做得对吗?它似乎可以工作,但我知道足够多的关于多线程编程的知识,知道仅因为今天它可以工作,并不意味着明天也可以。
其次,我想在我的进度窗口中添加一个取消按钮,以便能够取消进程。最好的方法是什么?我理解最终我将得到一个“cancelRequested”布尔标志,由工作线程定期检查,但我如何从进度窗口线程设置这个标志?