C#定时器和随机数

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
//using example3.RandomHelp;
namespace example3
{
  public partial class MainForm : Form
  {
    Timer timer = new Timer();
    int zheng;
    int shi;
     
    public MainForm()
    {
      InitializeComponent();
      button1.Click+=button1_Click;
     button2.Click+=button2_Click;
      
      // if (textBox3.Text != null)
      // {
       //  string m = textBox3.Text;
       
    }
 
    void timer_Tick(object sender, EventArgs e)
    {
      //throw new NotImplementedException();
    //  radioButton2_Click(null,null);
     //  double r = (example3.RandomHelp.GetIntRandomNumber(int.Parse(textBox1.Text), int.Parse(textBox2.Text)));
    //  string s = r.ToString();
    //   label4.Text = s;
      if (zheng == 1)
      {
        int r = (example3.RandomHelp.GetIntRandomNumber(int.Parse(textBox1.Text), int.Parse(textBox2.Text)));
        string s = r.ToString();
        label4.Text = s;
      }
       if (shi == 2)
      {
        double r = (example3.RandomHelp.GetDoubleRandomNumber(int.Parse(textBox1.Text), int.Parse(textBox2.Text)));
          string s = r.ToString();
          label4.Text = s;
       }
    }
    //整数
    private void radioButton1_CheckedChanged(object sender, EventArgs e)
    {
      RadioButton r = sender as RadioButton;
      if (r.Checked == true)
      {
        zheng = 1;
      }
    }
    //实数
    private void radioButton2_CheckedChanged(object sender, EventArgs e)
    {
      RadioButton r = sender as RadioButton;
      if (r.Checked == true)
      {
        shi = 2;
      }
    }
    //开始
    private void button1_Click(object sender, EventArgs e)
    {
      timer.Interval = int.Parse(textBox3.Text);
      //timer.Interval = 500;
      timer.Tick += timer_Tick; 
      timer.Start();
       
    }
    //停止
    private void button2_Click(object sender, EventArgs e)
    {
      timer.Stop();
    }
   
  }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//using System.Windows.Forms.Timer;
 
namespace example3
{
  class RandomHelp
  {
    public static int GetIntRandomNumber(int min,int max)
    {
      Random r=new Random();
      int ran=r.Next(min, max + 1);
 
    return ran;
    }
    //很不错的算法
    public static double GetDoubleRandomNumber(int min,int max)
    {
      Random r = new Random();
 //很不错的算法    
      double m=r.NextDouble() * max;
      double n = r.NextDouble() * min;
      
      if(m-n>2.0)
      return m;
      else
      return n+3.0;
    }
  }
}