CODEWITHSUNDEEP
c#multithreadingwinformsthread-safety
JonJon2244
JonJon2244

Reputation: 75

Opening a new child form while in a thread

I am trying to open a new child form (BuyNow Form) when a thread exits and I determined license type to be expired. During a thread, I open a new process that does the license calculation and sends the information back to the Main process. The problem is, thread gets exited before all the information is received so I can't open the BuyNow form, because it doesn't know the license is expired yet.

This is the code:

        BackgroundWorker BW = new BackgroundWorker();
        BW.DoWork += (sender, e) =>
            {
                Process.Start("LicenseManager.exe", "-Check");
                // PSI Info, DataRecieved Event Args and etc.. included in Process.
                // Opens the process which takes about 5 second to calculate and post
                // license information. Then LicenseMode changes to TrialExpired
                // if not activated and trial expired.
            };
        BW.RunWorkerCompleted += (sender, e) =>
            {
                // This never gets executed because License is not changed to TrialExpired by the time BW is completed.
                if (LicenseMode == License.TrialExpired)
                {
                   new BuyNowForm().Show();
                }
            };
        BW.RunWorkerAsync();

I tried to open the BuyNowForm while in a thread but that freezes the newly created form. I don't want to try Thread.Sleep and wait few extra seconds for the process to send information. Thread.Join() seems to freeze the Main UI for few seconds. Process.Exited += does not work either, cuz the process was created in a thread so when it exits, BuyNowForm is still being created in a thread.

Anything you guys can think off?

Upvotes: 2

Views: 160

Answers (1)

JeffRSon
JeffRSon

Reputation: 11176

The Process class has a WaitForExit method. This will wait, surprise, until the process exits. You have to do that (obviously) in DoWork.

You should not open a form from another thread (which is true for DoWork). RunWorkerCompleted would be the correct way, because it is executed in main GUI thread.

Upvotes: 3

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