如何动态创建移动面板

Question

I am currently creating a moving panel in x axis triggered by a button on my winform it work great but now i want to add multiple panels every time the button is click. The problem is i created the panel via toolbox and attached it on a timer_tick event and i believe this can be done only once so my plan is to create a dynamic panel and a timer don't know if its the correct approach.

Here is my code

   private void button2_Click(object sender, EventArgs e)
     {
            start();
     } 

    private void start(){

        timer1.Enabled = true;
    }

    private void timer1_Tick(object sender, EventArgs e )
    {
        panel_1.BackColor = Color.Green;
        int x = panel_1.Location.X;
        int y = panel_1.Location.Y;

        panel_1.Location = new Point(x + 25, y);
        xy_text.Text = x + ","+ y;
        if (x > this.Width)
        {
            timer1.Stop();
        }
    }

Answer 1

As per TaW's suggestion - see comments for commentary:

    private List<Panel> _panels = new List<Panel>(); //class level list to track the panels


    private void button2_Click(object sender, EventArgs e)
    {
        //create a new panel when the button is clicked
        var p = new Panel();
        p.Size = new Size(10, 10);
        p.Location = new Point(10, DateTime.Now.Second * (this.Height / 60)); //"random" Y so they don't pile up
        p.BackColor = Color.Green;

        this.Controls.Add(p);                           //add panel to form
        _panels.Add(p);                                 //add panel to list

        timer1.Enabled = true;                          //animate
    }


    private void timer1_Tick(object sender, EventArgs e)
    {
        for (int i = _panels.Count - 1; i >= 0; i--)    //use a backwards int indexed loop because we are potentially removing items from the list. 
        {                                               //Working backwards is the easiest way to not have to fiddle the index upon removal

            var p = _panels[i];                         //temp reference to a panel in the list, not related to 'var p' in the button click
            p.Left += 25;                               //move it
            if (p.Left > this.Width)                    //panel that is off screen?
                _panels.RemoveAt(i);                    //stop moving it then
        }

        if (_panels.Count == 0)                         //no more panels to move?
            timer1.Stop();                              //stop the timer

    }

You should look to implement some logic that removes your invisible panels from the this.Controls collection, if you don't have a use for them any more.

Answer 2

Here is a quick example I wrote, here I use 1 timer to handle all panels, if you want it smoother, make the movement delta smaller (from 25 to something lower) and increase the tick rate of your timer, you could also try to use a timer for each panel individually, but that would be overkill in my opinion.

Edit: If you wanted really accurate positioning and animation, you need to use more exact movement with doubles, and round to integers for the animation itself, use DateTime.Now to determine the distance travelled in a given time very exact, the timer doesn't determine the distance, it only updates the position:

public partial class MainForm : Form
{
    // X directional speed in pixels per second
    const int XSpeed = 400;

    private List<AnimationPanel> _panels = new List<AnimationPanel>();

    public MainForm()
    {
        InitializeComponent();
    }

    private void OnButtonStartClick(object sender, System.EventArgs e)
    {
        AnimationPanel newPanel = new AnimationPanel
        {
            Bounds = new Rectangle(10, 10, 50, 50),
            BorderStyle = BorderStyle.FixedSingle,
        };

        _panels.Add(newPanel);
        Controls.Add(newPanel);

        newPanel.StartBounds = newPanel.Bounds;
        newPanel.StartTime = DateTime.Now;

        _timer.Enabled = true;
    }

    private void OnTimerTick(object sender, System.EventArgs e)
    {
        for (int i = _panels.Count - 1; i >= 0; i--)
        {
            AnimationPanel currentPanel = _panels[i];

            DateTime startTime = currentPanel.StartTime;
            int xDelta = (int)Math.Round((DateTime.Now - startTime).TotalSeconds * XSpeed, 0);

            Point newLocation = new Point(currentPanel.StartBounds.X + xDelta, currentPanel.StartBounds.Y);

            // Check before or after collision (in this example before replacing the AnimationPanel)
            if (newLocation.X > this.Width)
            {
                // I chose to remove after it reaches the edge, do whatever you want
                _panels.RemoveAt(i);
                Controls.Remove(currentPanel);
            }
            else
            {
                currentPanel.Location = newLocation;
            }
        }

        if (_panels.Count == 0)
        {
            _timer.Enabled = false;
        }
    }

    private class AnimationPanel : Panel
    {
        public Rectangle StartBounds { get; set; }
        public DateTime StartTime { get; set; }
    }
}

Answer 3

You can create your panel from code like this :

        // init properties 
        var newPanel = new Panel
        {
            Name="Panel1",
            BackColor = Color.Green, 
            Location = new Point(0, 0), // set the starting point
            Width = 100, Height = 100
        };


        Controls.Add(newPanel);