C#自定义控件有关问题

C#自定义控件问题
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication3
{
    public partial class UserControl1 : UserControl
    {
        private int count = 4;
        public int Count
        {
            get { return count; }
            set
            {
                count = value;
                this.Invalidate();
            }
        }
  
        public int index = 0;
 
        public string name = "";

        public Color color;
  
        public UserControl1()
        {
            InitializeComponent();
        }
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            Graphics g = e.Graphics;

            #region 定义颜色
            if (index <= count)
            {
                if (index == 1)
                {
                    color = Color.Red ;
                }
                if (index == 2)
                {
                    color = Color.Black;
                }
                if (index == 3)
                {
                    color = Color.Blue;
                }
                if (index == 4)
                {
                    color = Color.SkyBlue;
                }
            }
            else
            {
                count = index;
                if (index == 5)
                {
                    color = Color.Coral;
                }
                if (index == 6)
                {
                    color = Color.CornflowerBlue;
                }