c#Random 产生随机数

1.产生随机整数
        Random ra = new Random();
        int num = ra.Next(1,100);

        This.Label1.Text = num.ToString();
2.产生随机正负数
        Random ra = new Random();

        int num = ra.Next(-100,100);

        This.Label1.Text = num.ToString();

3.产生随机小数

        Random ra = new Random();

        Double num = ra.NextDouble();

        This.Label1.Text = num.ToString();