Problem of screen getting cleard

I understand now. Hmm... I am not an expert with gdi. I just did some workaround with your code. This is all I could think of right now. I'm not sure if we could preserve what's already painted in your form. I kept seeing in forums that it could be preserved if we use image. But I have no idea yet how to do it. Goodluck.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.Text;
using System.Windows.Forms;

namespace CreateShapes
{

    public partial class Form1 : Form
    {
        private System.Drawing.Bitmap myBitmap;
        public static int index;
        int FirstXCoordinate, FirstYCoordinate, SecondXCoordinate, SecondYCoordinate;
        bool mousePressed;
        Graphics[] g = new Graphics[100];
        GraphicsState gs;

        List rectangles = new List();

        public Form1()
        {
            InitializeComponent();
            this.MouseDown += new MouseEventHandler(Form1_MouseDown);
            //this.Paint += new PaintEventHandler(Form1_Paint);
            this.MouseWheel += new MouseEventHandler(Form1_MouseWheel);

            this.MouseUp += new MouseEventHandler(Form1_MouseUp);
        }

        void Form1_MouseWheel(object sender, MouseEventArgs e)
        {
            SecondXCoordinate = e.X;
            SecondYCoordinate = e.Y;
            //MessageBox.Show(e.X.ToString());

            if (mousePressed == true)
            {

                this.Paint += new PaintEventHandler(Form1_Paint);

                Refresh();
            }
            else
            {
                this.Paint -= new PaintEventHandler(Form1_Paint);
            }


        }
        void Form1_Paint(object sender, PaintEventArgs e)
        {

            g[index] = e.Graphics;


            myBitmap = new Bitmap(50, 50);
            Rectangle rect = new Rectangle(50, 50, 20, 20);
            g[index].DrawImage(myBitmap, 0, 0, 20, 20);

            g[index].DrawRectangle(new Pen(Color.Black), FirstXCoordinate, FirstYCoordinate, (SecondXCoordinate - FirstXCoordinate), (SecondYCoordinate - FirstYCoordinate));


            foreach (Rectangle rectangle in rectangles)
            {
                e.Graphics.DrawRectangle(Pens.Red, rectangle);
            }
        }

        void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            //for (int i = 0; i < index; i++)
            //{
            //    MessageBox.Show(index.ToString());
            //    g[i].DrawRectangle(new Pen(Color.Black), FirstXCoordinate, FirstYCoordinate, (SecondXCoordinate - FirstXCoordinate), (SecondYCoordinate - FirstYCoordinate));
            //}
            FirstXCoordinate = e.X;
            FirstYCoordinate = e.Y;
            mousePressed = true;
            MouseMove += new MouseEventHandler(Form1_MouseWheel);
        }
        void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            //MessageBox.Show("up");
            SecondXCoordinate = e.X;
            SecondYCoordinate = e.Y;
            ResetMouseEventArgs();
            mousePressed = false;
            //ImageConverter img = new ImageConverter();

            //g[index] = this.CreateGraphics();
            //this.Paint += new PaintEventHandler(Form1_Paint);

            //index++;

            rectangles.Add(new Rectangle(FirstXCoordinate, FirstYCoordinate, SecondXCoordinate - FirstXCoordinate, SecondYCoordinate - FirstYCoordinate));
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

This is my code.....


using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.Text;
using System.Windows.Forms;

namespace CreateShapes
{
    
    public partial class Form1 : Form
    {
        private System.Drawing.Bitmap myBitmap;
        public static int index;
        int FirstXCoordinate, FirstYCoordinate, SecondXCoordinate, SecondYCoordinate;
        bool mousePressed;
        Graphics[] g =new Graphics[100];
        GraphicsState gs;
        public Form1()
        {
            InitializeComponent();
            this.MouseDown += new MouseEventHandler(Form1_MouseDown);
            this.Paint += new PaintEventHandler(Form1_Paint);
            this.MouseWheel+=new MouseEventHandler(Form1_MouseWheel);
       
            this.MouseUp+=new MouseEventHandler(Form1_MouseUp);
        }
        
        void Form1_MouseWheel(object sender, MouseEventArgs e)
        {
            SecondXCoordinate = e.X;
            SecondYCoordinate = e.Y;
            //MessageBox.Show(e.X.ToString());

            if(mousePressed==true)
            {
                
                this.Paint += new PaintEventHandler(Form1_Paint);
                
                Refresh();
            }
            
        }
        void Form1_Paint(object sender, PaintEventArgs e)
        {

            g[index] = e.Graphics;
            
           
            myBitmap = new Bitmap(50, 50);
            Rectangle rect = new Rectangle(50, 50, 20, 20);
            g[index].DrawImage(myBitmap, 0, 0, 20, 20);
            
            g[index].DrawRectangle(new Pen(Color.Black), FirstXCoordinate, FirstYCoordinate, (SecondXCoordinate - FirstXCoordinate), (SecondYCoordinate - FirstYCoordinate));
            
            
        }

        void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            for (int i = 0; i < index; i++)
            {
                MessageBox.Show(index.ToString());
                g[i].DrawRectangle(new Pen(Color.Black), FirstXCoordinate, FirstYCoordinate, (SecondXCoordinate - FirstXCoordinate), (SecondYCoordinate - FirstYCoordinate));
            }
            FirstXCoordinate = e.X;
            FirstYCoordinate = e.Y;
            mousePressed = true;
            MouseMove += new MouseEventHandler(Form1_MouseWheel);
        }
        void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            //MessageBox.Show("up");
            SecondXCoordinate = e.X;
            SecondYCoordinate = e.Y;
            ResetMouseEventArgs();
            mousePressed = false;
            ImageConverter img = new ImageConverter();
             
            g[index] = this.CreateGraphics();
            this.Paint += new PaintEventHandler(Form1_Paint);
            
            index++;
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

Could you post some code related to the drawing of the shape.