Purple Rain in C#

Question

I'm Trying to make a purple rain in c# windows forms, just like the one in this video https://www.youtube.com/watch?v=KkyIDI6rQJI Hes using an ide called processing with java programming language.

Here's my code so far:

using System;
using System.Diagnostics;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace PurpleRain
{

public partial class MainForm : Form
{
    public MainForm()
    {

    }
    float x=150;
    float y=1;
    float yspeed=1;

    public void fall()
    {
        y=y+yspeed;
        if (y>=350)
        {
            y=0;
        }
    }
    public void show(float a,float b)
    {
        Graphics g;
        g = this.CreateGraphics();
        Pen myPen = new Pen(Color.MediumPurple);
        myPen.Width = 2;
        Pen myErase = new Pen(Color.Lavender);
        myErase.Width = 2;
        g.DrawLine(myErase, a, b-1, a, b+15);
        g.DrawLine(myPen, a, b, a, b+15);
    }

    void draw()
    {
        for (int i=0;i<10;i++){
            show(x,y);
            fall(); 
        }
    }   

    void Timer1Tick(object sender, EventArgs e)
    {
        draw();
    }
}

What this code does is draw a single purple line and make it fall to the bottom by erasing the previous drawn line. My problem is adding this purple line maybe a hundred to simulate a rain like in the video and having them start at random x and y positions as well. I've tried loops, list to no avail.

Answer 1

Not the best code, but it can be a good start for something better:

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        List<Drop> rain = new List<Drop> (); // keeps all drops in one place
        Random rnd = new Random ();          // for generating random numbers


        public Form1 ()
        {
            InitializeComponent ();

            for (int i = 0; i < 100; i++) // creates 100 drops at random position and with random speed
                rain.Add (CreateRandomDrop ());
        }


        private Drop CreateRandomDrop ()
        {
            return new Drop // create drop with random position and speed
            {
                Position = new PointF (rnd.Next (this.Width), rnd.Next (this.Height)),
                YSpeed   = (float) rnd.NextDouble () * 3 + 2 // 2..5
            };
        }


        private void UpdateRain () // changes Y position for each drop (falling), also checks if a drop is outside Main form, if yes, resets position to 0
        {
            foreach (var drop in rain)
            {
                drop.Fall ();

                if (drop.Position.Y > this.Height)
                    drop.Position.Y = 0;
            }
        }


        private void RenderRain ()
        {
            using (var grp = this.CreateGraphics ()) // using will call IDisposable.Dispose
            {
                grp.Clear (Color.DarkBlue);

                foreach (var drop in rain)
                    grp.DrawLine (Pens.White, drop.Position, new PointF (drop.Position.X, drop.Position.Y + 3));
            }
        }


        private void timer1_Tick (object sender, EventArgs e)
        {
            UpdateRain ();
            RenderRain ();
        }
    }


    class Drop
    {
        public PointF Position;
        public float  YSpeed;

        public void Fall () => Position.Y += YSpeed;
    }
}