當我從不使用Invoke或BeginInvoke時，無法呼叫Invoke或BeginInvoke錯誤

我是 C# 和異步編程的新手，所以我遇到的問題的解決方案可能很簡單（或者不是？！）。

這是問題：

• 我有一個 onClick 函式，它創建一個新的 UIControl 并將其作為新選項卡添加到當前表單中。
• 我先讓它同步運行并且沒有崩潰，但 UI 被阻塞了幾秒鐘，因為提供給此選項卡的資料需要大量計算。
• 我將 onclick 移動到 async 并在 Control 的 datprocessing 函式上添加了一個等待，但我現在得到了臭名昭著的：

“在創建視窗句柄之前，不能在控制元件上呼叫 Invoke 或 BeginInvoke”。

private async void btnNewTab_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.Multiselect = true;
            openFileDialog.Filter = "*.test";
            DialogResult dialogResult = openFileDialog.ShowDialog();

            if (dialogResult == DialogResult.OK)
            {
                //Display a basic loading Control while the other control is being prepared
                TabPage myTabPage = new TabPage("loading");
                LoadingControlPanel loadingPanel = new LoadingControlPanel();
                loadingPanel.Dock = DockStyle.Fill;
                myTabPage.Controls.Add(loadingPanel);
                tabControl.TabPages.Add(myTabPage);
                tabControl.SelectTab(myTabPage);

                //Load Data from files
                List<DataFile> result = await Task.Run(() => loadFiles(openFileDialog.FileNames));
                
                // create Control to display the data loaded
                MyTabControl newPanel = new MyTabControl();
                newPanel.Dock = DockStyle.Fill;

                // provide Data to new control (long processing)
                await Task.Run(() => newPanel.processData(result));

                // rename Tab, remove loading Control and display the tab with the processed Data
                myTabPage.Text = "Loaded";
                myTabPage.Controls.Remove(loadingPanel);
                myTabPage.Controls.Add(newPanel);
            }
        }

崩潰總是在我呼叫函式“processData”時發生，但并不總是在同一位置。我有一些除錯行，它們的處理方式并不總是相同。

The crash tells me the issue in on the line: "Application.Run(new FormMain());"

static void Main()
        {
            Application.SetHighDpiMode(HighDpiMode.SystemAware);
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new FormMain());
        } 

Here is the full stack trace:

System.Reflection.TargetInvocationException HResult=0x80131604
Message=Exception has been thrown by the target of an invocation.
Source=System.Private.CoreLib StackTrace: at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Delegate.DynamicInvokeImpl(Object[] args) at System.Delegate.DynamicInvoke(Object[] args) at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme) at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) --- End of stack trace from previous location --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme) at System.Windows.Forms.Control.InvokeMarshaledCallbacks()
at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, WM msg, IntPtr wparam, IntPtr lparam) at Interop.User32.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.Interop.Mso.IMsoComponentManager.FPushMessageLoop(UIntPtr dwComponentID, msoloop uReason, Void* pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(msoloop reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(msoloop reason, ApplicationContext context) at System.Windows.Forms.Application.Run(Form mainForm) at Program.Main() in Program.cs:line 22

This exception was originally thrown at this call stack: [External Code]

Inner Exception 1: InvalidOperationException: Invoke or BeginInvoke cannot be called on a control until the window handle has been created.

What on earth am I doing wrong with all this?

uj5u.com熱心網友回復：

問題是Task.Run(() => newPanel.processData(result))，這只能在 processData() 不接觸任何 UI 內容時起作用（但為什么它會成為面板的一部分？）

您只能使用 Task.Run() 處理內容，然后在主執行緒的 UI 中加載結果。

看看你能不能讓它看起來像：

//await Task.Run(() => newPanel.processData(result));
var data = await Task.Run(() => ProcessData(result));
newPanel.AcceptData(data);

LoadData 和 ProcessData() 最好是某些服務類的一部分，而不是您的 Form。但那是關于架構，而不是關于直接問題。

uj5u.com熱心網友回復：

這段代碼在這里

TabControl newPanel = new TabControl();
newPanel.Dock = DockStyle.Fill;

// provide Data to new control (long processing)
await Task.Run(() => newPanel.processData(result));

嘗試創建一個新的 TabControl，但從不顯示它，因此它從來沒有關聯的視窗句柄。這與您是同步還是異步進行資料處理完全無關。

您似乎也缺少一些相關代碼，因為System.Windows.Forms.TabControl沒有processData方法。

標籤：c# asynchronous async-await invoke

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