ArrayList

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1

Hey, i want to save the Positions of Points i draw on the Screen in an Array List, and then later when i press a button, draw that Points back on the screen.
When i type pos[i]. it does’t show me that i could use the properties x and y.

The commented line is not working like that, how could i make it work?

Thank you, and sry if this is a stupid beginners Question…

class Position

    class Position
    {
        uint x;
        public uint X
        {
            get { return x; }
            set { x = value; }
        }

        uint y;
        public uint Y
        {
            get { return y; }
            set { y = value; }
        }

        public Position(uint _x, uint _y)
        {
            this.x = _x;
            this.y = _y;
        }
    }

class Program

public partial class Program
    {
        static uint r = 1;
        ArrayList pos = new ArrayList();
        void ProgramStarted()
        {
            display.SimpleGraphics.AutoRedraw = true;

            display.WPFWindow.TouchDown += new Microsoft.SPOT.Input.TouchEventHandler(WPFWindow_TouchDown);
            display.WPFWindow.TouchUp += new Microsoft.SPOT.Input.TouchEventHandler(WPFWindow_TouchUp);

            display.WPFWindow.TouchMove += new Microsoft.SPOT.Input.TouchEventHandler(WPFWindow_TouchMove);

            button.ButtonPressed += new Button.ButtonEventHandler(button_ButtonPressed);
            button1.ButtonPressed += new Button.ButtonEventHandler(button1_ButtonPressed);
 
            display.SimpleGraphics.BackgroundColor = GT.Color.Black;
            display.WPFWindow.Invalidate();

            Debug.Print("Programm gestartet");
        }

        void WPFWindow_TouchMove(object sender, Microsoft.SPOT.Input.TouchEventArgs e)
        {
            display.SimpleGraphics.DisplayEllipse(GT.Color.Blue, (uint)e.Touches[0].X, (uint)e.Touches[0].Y, r, r);
            Position p = new Position((uint)e.Touches[0].X, (uint)e.Touches[0].Y);
            pos.Add(p);  
        }

        void WPFWindow_TouchDown(object sender, Microsoft.SPOT.Input.TouchEventArgs e)
        {
            multicolorLed.TurnGreen();
        }

        void WPFWindow_TouchUp(object sender, Microsoft.SPOT.Input.TouchEventArgs e)
        {
            multicolorLed.TurnOff();
        }

        void button_ButtonPressed(Button sender, Button.ButtonState state)
        {
            display.SimpleGraphics.Clear();
            pos.Clear();
        }


        void button1_ButtonPressed(Button sender, Button.ButtonState state)
        {
            display.SimpleGraphics.Clear();
            for (int i = 0; i < pos.Count; i++)
            {
                display.SimpleGraphics.DisplayEllipse(GT.Color.Blue, pos[i].x, pos[i].y, r, r); // This line is wat doesnt work like that, can anyone tell me how i could do that?
            }
        }
    }
2

Saying “it does not work” is a bit vague. I assume you are getting a compiler error.

The ArrayList class stores the things you add to it as an Object. When you take it out of the ArrayList you need to cast it to the correct object type.

3

Thank You :wink:

It works like that:

 void button1_ButtonPressed(Button sender, Button.ButtonState state)
        {
            display.SimpleGraphics.Clear();
            for (int i = 0; i < pos.Count; i++)
            {
                Position tmp = (Position)pos[i];
                display.SimpleGraphics.DisplayEllipse(GT.Color.Blue, tmp.X, tmp.Y, r, r); 
            }
        }