的BackgroundWorker的ShowDialog导致应用程序停止

Question

我一直在努力实现一个BackgroundWorker到我的应用程序，到目前为止，还没有顺利。在一个新线程中，我想打开一个新的表单，该表单将包含一个进度条和一个标签以报告进度，但是，这样做效果不佳。当我调用ShowDialog时，应用程序不再响应。这是因为我的代码是从我的Form1运行的，而且我正在显示WorkingForm？此外，这可以实施更清洁？

private void button14_Click(object sender, EventArgs e) 
{ 
    List<object> param = new List<object>(); 
    object[] objectparams = new object[1]; 
    objectparams[0] = null; 
    Opera opera = new Opera(); 
    System.Reflection.MethodInfo clearOpera = opera.GetType().GetMethod("ClearOpera"); 
    param.Add(clearOpera); 
    param.Add(opera); 
    param.Add(objectparams); 
    backgroundWorker1.RunWorkerAsync(param); 
} 

private void button2_Click_1(object sender, EventArgs e) 
{ 
    Browser.cancelPending = true; 
} 
private delegate void getnewform(); 

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) 
{ 
    mainForm main = new mainForm(); 
    TestURLGUI4.Form1 form = (TestURLGUI4.Form1)Application.OpenForms[0]; 
    var variab = (bool)form.Invoke(new getnewform(main.AskForConfirmation)); 
     List<object> param = e.Argument as List<object>; 

     List<object> result = new List<object>(); 
     var method = param[0] as MethodInfo; 
     object[] parameters = param[2] as object[]; 
     if (parameters[0] == null) 
     { 
      result.Add(method.Invoke(param[1], null)); 
      result.Add(false); 
     } 
     else 
     { 
      result.Add(method.Invoke(param[1], parameters)); 
      if (parameters.Contains(true)) 
       result.Add(true); 
     } 
     int progress = (100 * Browser.progressValue)/Browser.progressMax; 

     backgroundWorker1.ReportProgress(progress); 

     // If the BackgroundWorker.CancellationPending property is true, cancel 
     if (backgroundWorker1.CancellationPending) 
     { 
      Console.WriteLine("Cancelled"); 
      Browser.cancelPending = true; 
     } 
     e.Result = result; 
} 

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) 
{ 
     TestURLGUI4.WorkingForm form = (TestURLGUI4.WorkingForm)Application.OpenForms[1]; 
     form.progressBar1.Value = e.ProgressPercentage; 

     form.label1.Text = Browser.progressValue + "/" + Browser.progressMax; 
     Application.DoEvents(); 
} 

private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) 
{ 
    List<object> param = e.Result as List<object>; 
    if (e.Cancelled == false && param.Contains(true)) 
    { 
     Display.DisplayURLs(param[0] as SortableBindingList<URL>); 
     TestURLGUI4.WorkingForm form = (TestURLGUI4.WorkingForm)Application.OpenForms[1]; 
     MessageBox.Show("Done"); 

    } 
    else if (e.Cancelled == false && param.Contains(false)) 
    { 
     TestURLGUI4.WorkingForm form = (TestURLGUI4.WorkingForm)Application.OpenForms[1]; 
     MessageBox.Show("Done"); 
    } 


} 

    public class mainForm 
{ 
public void AskForConfirmation() 
{ 
    TestURLGUI4.Form1 form = (TestURLGUI4.Form1)Application.OpenForms[0]; 
    var workingForm = new TestURLGUI4.WorkingForm(); 
    workingForm.ShowDialog(form); 
    workingForm.DialogResult = DialogResult.None; 

} 
} 

编辑： 好吧，我已经根据建议更新了我的代码，而现在，这将产生在System.Windows.Forms.dll中一个stackoverflowexception：

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) 
{ 
    mainForm main = new mainForm(); 
    TestURLGUI4.Form1 form = (TestURLGUI4.Form1)Application.OpenForms[0]; 
     List<object> param = e.Argument as List<object>; 
     List<object> result = new List<object>(); 
     var method = param[0] as MethodInfo; 
     object[] parameters = param[2] as object[]; 
     if (parameters[0] == null) 
     { 
      result.Add(method.Invoke(param[1], null)); 
      result.Add(false); 
     } 
     else 
     { 
      result.Add(method.Invoke(param[1], parameters)); 
      if (parameters.Contains(true)) 
       result.Add(true); 
     } 
     int progress = (100 * Browser.progressValue)/Browser.progressMax; 

     backgroundWorker1.ReportProgress(progress); 

     // If the BackgroundWorker.CancellationPending property is true, cancel 
     if (backgroundWorker1.CancellationPending) 
     { 
      Console.WriteLine("Cancelled"); 
      Browser.cancelPending = true; 
     } 
     e.Result = result; 


} 

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) 
{ 
    TestURLGUI4.Form1 form1 = (TestURLGUI4.Form1)Application.OpenForms[0]; 
    if (Application.OpenForms.Count >= 2) 
    { 
     TestURLGUI4.WorkingForm form2 = (TestURLGUI4.WorkingForm)Application.OpenForms[1]; 
     form2.progressBar1.Value = e.ProgressPercentage; 

     form2.label1.Text = Browser.progressValue + "/" + Browser.progressMax; 
     Application.DoEvents(); 
    } 
    else if(Application.OpenForms.Count == 1) 
    { 
     var workingForm = new TestURLGUI4.WorkingForm(); 
     workingForm.ShowDialog(form1); 
    } 
} 

Answer 1

BackgroundWorker的目的是调用另一个线程（而不是UI线程）上的代码。通过在DoWork方法中调用Invoke，您完全可以规避BackgroundWorker的目的。在启动工作人员之前，完成所有UI的工作。如果您需要与而工人正在工作的用户交互，这样做在ProgressChanged处理程序 - 它运行在UI线程上，你不需要ProgressChanged使用Invoke。

通过调用DoWork UI的工作，你运行一个死锁的风险，这将挂程序

Answer 2

你不能上运行的UI其他线程。必须在主线程上。

实例化UI启动新线程之前。在新线程中，您想要使用的控件上使用跨线程调用方法。看这里例如http://msdn.microsoft.com/en-us/library/ms171728.aspx