C#

public void btnAccepted_Clicked(object sender, EventArgs e) {
    countAccepted++;
    Calc();
}

public void btnRejected_Clicked(object sender, EventArgs e) {
    countRejected++;
    Calc();
}

public void Calc() {
    int totalCount=countAccepted+countRejected;
    if (totalCount!=0) {
        int rejectedRate=100*countRejected/totalCount;
        textBoxAccepted.Text=countAccepted.ToString();
        textBoxRejected.Text=countRejected.ToString();
        textBoxRejectedRate.Text=rejectedRate.ToString()+" %";
    }
}

public void BarcodeReaderTextBox_TextChanged(object sender, EventArgs e) {
    // first decide which counter to increment, depending on ...
    ...
    // then recalculate
    Calc();
}

        private static Thread TimeoutThread; 
        private void Form1_Load(object sender, EventArgs e)
        {
            ThreadStart Job = new ThreadStart(TestTimeout);
            TimeoutThread = new Thread(Job) { IsBackground = true };
            TimeoutThread.Start(); 
        }

        private static void TestTimeout() 
        {
            while (true)
            {
                MessageBox.Show("Starting Work");
                try
                {
                    Thread.SpinWait(100000000);
                    MessageBox.Show("Finished Work");
                    Thread.Sleep(Timeout.Infinite);
                }
                catch (ThreadInterruptedException)
                {

                }                 
            }

        }

        private void button1_Click(object sender, EventArgs e)
        {
            TimeoutThread.Interrupt();
        } 
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