的BackgroundWorker的ShowDialog導致應用程序停止

Question

我一直在努力實現一個BackgroundWorker到我的應用程序，到目前爲止，還沒有順利。在一個新線程中，我想打開一個新的表單，該表單將包含一個進度條和一個標籤以報告進度，但是，這樣做效果不佳。當我調用ShowDialog時，應用程序不再響應。這是因爲我的代碼是從我的Form1運行的，而且我正在顯示WorkingForm？此外，這可以實施更清潔？

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; 

} 
} 

編輯： 好吧，我已經根據建議更新了我的代碼，而現在，這將產生在System.Windows.Forms.dll中一個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的目的是調用另一個線程（而不是UI線程）上的代碼。通過在DoWork方法中調用Invoke，您完全可以規避BackgroundWorker的目的。在啓動工作人員之前，完成所有UI的工作。如果您需要與而工人正在工作的用戶交互，這樣做在ProgressChanged處理程序 - 它運行在UI線程上，你不需要ProgressChanged使用Invoke。

通過調用DoWork UI的工作，你運行一個死鎖的風險，這將掛程序

Answer 2

你不能上運行的UI其他線程。必須在主線程上。

實例化UI啓動新線程之前。在新線程中，您想要使用的控件上使用跨線程調用方法。看這裏例如http://msdn.microsoft.com/en-us/library/ms171728.aspx