Invoke or beginInvoke cannot be called until the window handle has been created.

[amit_pansuria]

Hi all,

I m getting above metnioned error intermidently.

Scenario:
I am calling splash screen form from separate thread and then calling login screen.

Find here with attached code snippet.

[Mutant_Fruit]

I assume you also disabled the cross threading calls exception? Reenable it, then fix your code.

Never call winforms code from anything other than the main thread.

[darwen]

I assume you also disabled the cross threading calls exception? Reenable it, then fix your code.

Never call winforms code from anything other than the main thread.

He's doing the right thing - i.e. using Invoke/BeginInvoke to ensure that windows forms messages occur on the correct thread. However there appears to be a race condition occurring.

The condition arises because of the following two parts of the code :

Thread splashThread = new Thread(new ThreadStart(ShowSplash));
splashThread.Start();
// ...
objfrmSplash.Invoke(d); // point A

//...

// This is executed in a separate thread (see above)
static void ShowSplash()
{
    objfrmSplash = new frmSplash();
    objfrmSplash.ShowDialog();
}

Your code is getting to to point A before the thread has been executed and/or the dialog created and shown. That's a race condition.

You need to synchronise the calls - i.e. you have to ensure that the form has been shown & created before you call Invoke.

You can use an event to do this :

class Program
{
    static public string strCulture;
    static public Form objfrmSplash;
    static public ManualResetEvent _splashFormShown = new ManualResetEvent(false);

    // ...

        if (login.StartSession())
        {
            Form mainApp = new frmMainApp();
            _splashFormShown.WaitOne(); // wait until form has been created
            objfrmSplash.Invoke(d);
            d = null;
            Application.Run(mainApp);
        }
        else
        {
            _splashFormShown.WaitOne(); // wait until form has been created
            objfrmSplash.Invoke(d);
            d = null;
            Application.Exit();
        }

// ....

static void ShowSplash()
{
    objfrmSplash = new frmSplash();
    objfrmSplash.Load += new EventHandler(objfrmSplashLoadedEvent);
    objfrmSplash.ShowDialog();
}

static void objfrmSplashLoadedEvent(object sender, EventArgs args)
{
    _splashFormShown.Set();
}

Get the idea ? You hook into the form's loaded event (by which time the handle will have been created) and then signal the main thread that it's safe to proceed.

In future if one thread makes assumptions about the state of another thread you HAVE to ensure this with a signal as I've shown. Otherwise you'll get intermittent errors when the assumption you have made is not true and you get a race condition.

Darwen.

[AbhiZ]

Follow these step to resolve the above problem

1) Restart the computer.
2) Start the SQL SERVER 2008 setup.
3) Setup window will apear just focus on it and installation setup will be started in few second.
If it displaying the error message again again perform these above steps.

Enjoy the installation..........

For more query mail me at:-
abhizprogrammer@yahoo.com

[DataMiser]

Not only is this a really old thread but the post above which has revived it has nothing to do with the topic at hand.

[Sunil Ganta]

uncompress it with zip or Rar compression utility on desktop and try

[DataMiser]

Try what? Why? The thread is 3 years old I doubt the OP is still waiting for an answer.