有道题目是显示随机整数及其对应字符，就是字符什么意思，代码我写了

using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace _2._6作业5
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            Random ran = new Random();
            int a;
            String c;
            int RandKey = ran.Next(1, 100);
            a = RandKey;
            textBox1.Text = Convert.ToString(a);
            c = Convert.ToString(a);

            textBox2.Text = c;
        }
    }
}
我用电脑写了这个然后两个框框都显示随机数字，那个数字对应的字符什么意思及其对应转化格式给一个我参考啊