如何使用Invoke或BeginInvoke方法处理Windows窗体中的控件

Question

I get the following exception thrown:

Invoke or BeginInvoke cannot be called on a control until the window handle has been created.

I am using betterlistviewer and dotnetbar just modifying this code Registry cleaner but i am trying to invoke that all classes and controls in another form not in the main.

This is my code

    public Registry_Scan()
    {
        InitializeComponent();
        StartScanning GeekStartCleaning = StartScanning.GeekCreateControl();

        GeekStartCleaning.GeekOnAllScanComplete += GeekOnScanComplete;

        this.GeekPanel.Controls.Add(GeekStartCleaning);
    }
    ScanComplete GeekOnComplete = new ScanComplete();
    public void GeekOnScanComplete(ref List<BetterListViewGroup> _GeekListOfGroupTargets)
    {

        List<BetterListViewGroup> GeekListOfGroupTargets = _GeekListOfGroupTargets;

        GeekOnComplete.GeekAddRangeTargets(ref GeekListOfGroupTargets);
        GeekOnComplete.Show();
        this.GeekPanel.Invoke(new MethodInvoker(() =>
        {
            this.GeekPanel.Controls.Clear();
            this.GeekPanel.Controls.Add(GeekOnComplete);
        }));
    }

I don't know whats wrong please help

System.InvalidOperationException HResult=0x80131509 Message=Invoke or BeginInvoke cannot be called on a control until the window handle has been created. Source=System.Windows.Forms StackTrace: at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous) at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args) at System.Windows.Forms.Control.Invoke(Delegate method) at GeekCleaner.Registry_Scan.GeekOnScanComplete(List`1& _GeekListOfGroupTargets) in C:\\Users\\RamRo\\source\\repos\\GeekVersion1\\GeekCleaner\\GeekCleaner\\RegistryScan.cs:line 34 at GeekCleaner.UserPanel.StartScanning.GeekStartScanning() in C:\\Users\\RamRo\\source\\repos\\GeekVersion1\\GeekCleaner\\GeekCleaner\\UserPanel\\StartScanning.cs:line 139 at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.Exe cutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()

Answer 1

I can't really tell from your code what exactly the problem is. But it will most certainly be a multitasking problem.

The Exception is easy to reproduce in a very simple Application by just calling Invoke before the InitializeComponent call.

Since all your shown code looks synchronous and is beyond Registry_Scan's InitializeComponent I don't think the problem is there.

So you should check StartScanning.GeekCreateControl() and other calls for possible multitasking issue which will trigger an Invoke before InitializeComponent like this one:

public partial class Form1 : Form
{
    public Form1()
    {
        Task.Factory.StartNew(() =>
        {
            this.Invoke(new Action(() =>
            {
                this.Text = "UI Change";
            }));
        });

        InitializeComponent();
    }
}

Hope this helps

Answer 2

I think there is InvokeRequired property for checking if the form need invoke or not?

So should be like this one:

if(this.GeekPanel.InvokeRequired)
{
    this.GeekPanel.Invoke(new MethodInvoker(() =>
    {
        this.GeekPanel.Controls.Clear();
        this.GeekPanel.Controls.Add(GeekOnComplete);
    }));
}
else
{
    this.GeekPanel.Controls.Clear();
    this.GeekPanel.Controls.Add(GeekOnComplete);
}