计时器滴答事件中的动态按钮单击事件

Question

I have a grid with 9 buttons. In the timer tick event a random button is higlighted. If one clicks the higlighted button, a dynamic click event is created and within the click event the button is marked with a different color. The counterHits variable in the dynamic button click event is supposed to keep track of the highlighted buttons that were hit. Sometimes though it increases the variable more than by one. I cannot figure out why this is happening. Any help anyone?

public partial class Form1 : Form
{

    const int buttons = 9;
    int counterHits;
    int counterTicks;    
    int currentIndex;
    int lastIndex;
    bool hit = false;
    Random r;

    Timer timerGameLoop;
    Timer timerUpdateUI;
    public Form1()
    {
        InitializeComponent();

        timerGameLoop = new Timer();
        timerGameLoop.Interval = 1000;
        timerGameLoop.Tick += t_Tick;

        timerUpdateUI = new Timer();
        timerUpdateUI.Interval = 10;
        timerUpdateUI.Tick += timerUpdateUI_Tick;

        r = new Random();

    }

    // set up the grid and start
    private void btnStart_Click(object sender, EventArgs e)
    {
        for (int i = 0; i < buttons; i++)
        {
            var b = new Button();
            b.Size = new Size(100, 100);
            b.Margin = new Padding(0);
            b.BackColor = Color.White;
            flowLayoutPanel.Controls.Add(b);
        }
        timerGameLoop.Start();
        timerUpdateUI.Start();
    }


    // tick event ui update loop
    void timerUpdateUI_Tick(object sender, EventArgs e)
    {
        lblHitCounter.Text = "hits : " + counterHits.ToString();
        lblTickCounter.Text = "ticks : " + counterTicks.ToString();
    }

    // tick event game loop
    void t_Tick(object sender, EventArgs e)
    {
        // reset to white background if not clicked
        if (!hit)
            flowLayoutPanel.Controls[lastIndex].BackColor = Color.White;
        // highlight button to be clicked
        currentIndex = r.Next(buttons);
        lastIndex = currentIndex;
        flowLayoutPanel.Controls[currentIndex].BackColor = Color.Violet;

        // highligted button clicked
        flowLayoutPanel.Controls[currentIndex].Click += b_Click;

        hit = false;
        counterTicks++;
    }


    // highlighted button clicked event
    void b_Click(object sender, EventArgs e)
    {
        var b = (Button)sender;
        b.BackColor = Color.Olive;
        hit = true;
        counterHits++;
        b.Click -= b_Click;
    }

}

Answer 1

The following lines attaches b_Click to your button. That eventhandler is only removed if you press the button

flowLayoutPanel.Controls[currentIndex].Click += b_Click;

See the implementation of b_Click

    // highlighted button clicked event
    void b_Click(object sender, EventArgs e)
    {
        //Stugg
        b.Click -= b_Click;←Removed Here only if it is pressed
    }

This line indicates that some buttons have more than one EventHandler attached. Therefore when you click the button eventhandler runs more than once.