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namespace Test_Backgroundworker
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        //Fortschritt anzeigen
        void ShowProgress(string t)
        {
            // Make sure we're on the UI thread
            Debug.Assert(this.InvokeRequired == false);

            // Display progress in UI
            this.listBox1.Items.Add(t);
        }

        //Kommunikationsobject?
        class TestUserState
        {
            public readonly string t;
            
            //Konstruktor
            public TestUserState(string t)
            {
                this.t = t;
            }
        }

        //intensive Berechnungsfunktion
        void ToDo(string s)
        {
            //"Berechnung"

            MessageBox.Show("ToDo");
            

            // Report continuing progress
            this.backgroundWorker1.ReportProgress(0,new TestUserState(s));

            // Check for cancelation
            if (this.backgroundWorker1.CancellationPending) 
            { 
                return;
            }
        }

        //Backgroundworker starten
        //Buttonlogik
        private void Start(object sender, EventArgs e)
        {
            // Don't process if cancel request pending
            // (Should not be called, since we disabled the button...)
            if (this.backgroundWorker1.CancellationPending) { return; }

            // If worker thread currently executing, cancel it
            if (this.backgroundWorker1.IsBusy)
            {
                this.btnstart.Enabled = false;
                this.backgroundWorker1.CancelAsync();
                return;
            }
            
            // Set calculating UI
            this.btnstart.Text = "Cancel";

            MessageBox.Show("Start");
            // Begin asynchronously
            this.backgroundWorker1.RunWorkerAsync("Test");
        }
        
        //Backgroundworker Arbeitsmethode
        private void BW_DoWork(object sender, DoWorkEventArgs e)
        {
            MessageBox.Show("BW_DoWork");
            ToDo((string)e.Argument);

            // Indicate cancelation
            if (this.backgroundWorker1.CancellationPending)
            {
                e.Cancel = true;
            }

        }

        //Backgroundworker Fortschritt mitteilen
        private void BW_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            MessageBox.Show("ProgressChanged");
            // Show progress
            TestUserState progress = (TestUserState)e.UserState;
            ShowProgress(progress.t);
        }


    }
}