調用線程不能訪問該對象

Question

我看了一下這個錯誤很多帖子，但我不知道它如何能在我的解決方案來解決（（我有一個進度對話框，在IT-一些邏輯這是從大型機通過ButtonClick稱爲

void OnBtnClick(object sender, RoutedEventArgs e) 
{ 
    ProgressDialog dlg = new ProgressDialog(""); 
    dlg.Closing += new CancelEventHandler(dlg_Closing); 
    dlg.Closed += new EventHandler(dlg_Closed); 
    //dlg.AutoIncrementInterval = 0; 
    LibWrap lwrap = new LibWrap(); 
    DoWorkEventHandler handler = delegate 
    { 
     BitmapFrame bf = wrap.engine(BitmapFrame.Create(FXPhotoStudio.App 
                  .draggedImage), 
            this.fxPSEditorView); 
    }; 
    dlg.CurrentLibWrap = lwrap; 
    dlg.AutoIncrementInterval = 100; 
    dlg.IsCancellingEnabled = true; 
    dlg.Owner = Application.Current.MainWindow; 
    dlg.RunWorkerThread(0, handler); 
} 

也有此進度條的對話框

void dlg_Closed(object sender, EventArgs e) 
{ 
    try 
    { 
     mainFrameView.CurrentImage = effectedImage;//!error here! 
    } 
} 

的effectedImage是大型機的領域在封閉的情況下同一類（大型機）的處理程序。它由我的ProgressDialog設置。 我使ProgressDialog.cs如下：

(this.Owner as MainFrame).effectedImage = currentLibVrap.GetEffectedImage; 

currentLibVrap在OnBtnClick設置 - 見上 誰能幫我解決這個問題？

這是關閉ProgressBarDialog代碼：

private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) 
    { 
     if (!Dispatcher.CheckAccess()) 
     { 
     //run on UI thread 
     RunWorkerCompletedEventHandler handler = worker_RunWorkerCompleted; 
     Dispatcher.Invoke(DispatcherPriority.SystemIdle, handler, new object[] {sender, e}, null); 
     return; 
     } 

     if (e.Error != null) 
     { 
     error = e.Error; 
     } 
     else if (!e.Cancelled) 
     { 
     //assign result if there was neither exception nor cancel 

      (this.Owner as MainWindow).effectedImage = currentLibVrap.GetEffectedImage;//! ok there 

     result = e.Result; 
     } 

    //update UI in case closing the dialog takes a moment 
// progressTimer.Stop(); 
    progressBar.Value = progressBar.Maximum; 
    btnCancel.IsEnabled = false; 

    //set the dialog result, which closes the dialog 
    DialogResult = error == null && !e.Cancelled; 
} 

而且還有工作過程：

/// Launches a worker thread which is intended to perform 
/// work while progress is indicated, and displays the dialog 
/// modally in order to block the calling thread. 
/// </summary> 
/// <param name="argument">A custom object which will be 
/// submitted in the <see cref="DoWorkEventArgs.Argument"/> 
/// property <paramref name="workHandler"/> callback method.</param> 
/// <param name="workHandler">A callback method which is 
/// being invoked on a background thread in order to perform 
/// the work to be performed.</param> 


    public bool RunWorkerThread(object argument, DoWorkEventHandler workHandler) 
    { 
     if (autoIncrementInterval.HasValue) 
     { 
     //run timer to increment progress bar 
     progressTimer.Interval = TimeSpan.FromMilliseconds(autoIncrementInterval.Value); 
     progressTimer.Start(); 
     // LibWrap lwrap = new LibWrap(); 
     // BitmapFrame bf = lwrap.engine(BitmapFrame.Create(FXPhotoStudio.App.draggedImage));//(aa.Image); 

     } 

     //store the UI culture 
     uiCulture = CultureInfo.CurrentUICulture; 

     //store reference to callback handler and launch worker thread 
     workerCallback = workHandler; 
     worker.RunWorkerAsync(argument); 

     //display modal dialog (blocks caller) 
     return ShowDialog() ?? false; 
    } 

/// <summary> 
/// Worker method that gets called from a worker thread. 
/// Synchronously calls event listeners that may handle 
/// the work load. 
/// </summary> 
private void worker_DoWork(object sender, DoWorkEventArgs e) 
{ 
    try 
    { 
    //make sure the UI culture is properly set on the worker thread 
    Thread.CurrentThread.CurrentUICulture = uiCulture; 
    //invoke the callback method with the designated argument 
    workerCallback(sender, e); 
    } 
    catch (Exception) 
    { 
    //disable cancelling and rethrow the exception 
    //Dispatcher.BeginInvoke(DispatcherPriority.Normal, 
    //      (SendOrPostCallback) delegate { btnCancel.SetValue(Button.IsEnabledProperty, false); }, 
    //      null); 
    return; 
    //throw; 
    } 
} 

Answer 1

您可以使用Dispather.Invoke或Dispatcher.BeginInvoke。它們都會調用UI線程的調用（這就是你的錯誤所在），BeginInvoke是爲在後臺線程中運行繁重的操作而設計的，而Invoke只是一個編組器，所以對於你的類型任務，我會堅持最後一個一。

這裏是你如何做到這一點（假設mainFrameView.CurrentImage是Image型的，否則只是改變中不管它是什麼）：

C＃

更新1使用的參數，以避免一個唯一的名稱與現有的變量名稱保持一致。

mainFrameView.Dispatcher.Invoke(new Action<object>((myImage2012) => 
{ mainFrameView.CurrentImage = (Image)myImage2012; }), 
new object[1] { effectedImage }); 

Answer 2

你需要使用Dispatcher.BeginInvoke做調度它UI線程（調度和立刻返回）或Dispatcher.Invoke （阻塞，直到行動派遣）

這是因爲，在默認情況下，線程模型的應用程序是單threa代客公寓（STA）。這意味着，僅螺紋，其創建的UI元素，能夠與它進行交互，其他線程，它想做的事與UI元素的東西，必須調度對元素UI線程他們的行動

void dlg_Closed(object sender, EventArgs e) 
{ 
    try 
    { 
     mainFrameView.CurrentImage = effectedImage;//!error here! 
    } 
} 

確定UI線程發送此事件？你有沒有嘗試調度設置CurrentImage？ 你能不能請簡化你的代碼，只留下相關的方法？

UPD：我的意思是，你試圖派遣CurrentImage設置？

Application.Current.MainWindow.Dispatcher.BeginInvoke(new Action(()=> 
              { 
               mainFrameView.CurrentImage = effectedImage; 
              }));