C#中随机数和定时器的使用

C#中的定时器使用：

namespace SYA3
{
    public partial class Form1 : Form
    {
        int Flag = 0;    //redio button标志
        Timer tmr;
        float size;
        public Form1()
        {
            InitializeComponent();
            tmr = new Timer();  //申明定时器
            size = Result.Font.Size;//保存最初字体

        }

        private void label2_Click(object sender, EventArgs e)
        {

        }

        private void label3_Click(object sender, EventArgs e)
        {

        }

        private void Begin_Btn_Click(object sender, EventArgs e)
        {//由于Lable中的字体是只读的，所以在此必须重新画字体大小

            Result.Font= new System.Drawing.Font("宋体", size,
            System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
            tmr.Tick += new EventHandler(tmr_Elapsed); //在此设置定时器的事件委托,即在特定的时间该需要做什么
            tmr.Interval = int.Parse(Time_Edit.Text);  //设置时间间隔
            tmr.Start();                               //让定时器开始定时处理事情
        }

        private void End_Btn_Click(object sender, EventArgs e)
        {
            tmr.Stop();
            Result.Font = new System.Drawing.Font("宋体", 2*size,
                System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
        }

        private void groupBox2_Enter(object sender, EventArgs e)
        {

        }

        private void Min_edit_TextChanged(object sender, EventArgs e)
        {

        }

        private void radioButton1_CheckedChanged(object sender, EventArgs e)
        {
            Flag = 0;
        }

        private void radioButton2_CheckedChanged(object sender, EventArgs e)
        {
            Flag = 1;
        }
        public void tmr_Elapsed(object sender, EventArgs e)
        {
            Random rand = new Random();
            if (Flag == 0)
            {
                Result.Text = rand.Next(int.Parse(Min_edit.Text), int.Parse(Max_Edit.Text)) + "";
            }
            else
                Result.Text = rand.NextDouble() + "";
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }
}