二、八、十、十六进制相互转换

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

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //string s = zhuanhuan1(int.Parse(textBox1.Text), 2);//10转2
            //textBox2.Text = s;

            //string s1 = zhuanhuan1(int.Parse(textBox1.Text), 8);//10转8
            //textBox3.Text = s1;

            //string s2 = zhuanhuan1(int.Parse(textBox1.Text), 16);//10转16
            //textBox4.Text = s2;

            double s3 = zhuanhuan3(textBox4.Text, 16);//8转10
            textBox1.Text = s3.ToString();

            //double s4 = zhuanhuan2(textBox3.Text, 8);//8转10
            //textBox1.Text = s4.ToString();

            //double s4 = zhuanhuan2(textBox2.Text, 2);//2转10
            //textBox1.Text = s4.ToString();
        }
        private string zhuanhuan1(int a,int jinzhi)//转换为十进制
        {
            string jieguo = "";
            while (true)
            {
                if (jinzhi==2||jinzhi==8)
                {
                    string s = (a % jinzhi).ToString();
                    jieguo = s + jieguo;
                    a = a / jinzhi;
                    if (a==0)
                    {
                        break;
                    }
                }
                else if(jinzhi==16)
                {
                    int yushu = a % jinzhi;
                    string b = "";
                    if (yushu == 10)
                    {
                        b = "A";
                    }
                    else if (yushu == 11)
                    {
                        b = "B";
                    }
                    else if (yushu == 12)
                    {
                        b = "C";
                    }
                    else if (yushu == 13)
                    {
                        b = "D";
                    }
                    else if (yushu == 14)
                    {
                        b = "E";
                    }
                    else if (yushu == 15)
                    {
                        b = "F";
                    }
                    else
                    {
                        b = yushu.ToString();
                    }
                    jieguo = b + jieguo;
                    a = a / jinzhi;
                    if (a==0)
                    {
                        break;   
                    }
                }
            }
            return jieguo;
        }
        private double zhuanhuan2(string a, double  zhuanjinzhi)//把进制为zhuanjinzhi的进制数转换为十进制
        {
            double sum = 0;
            for (int i = 0; i < a.Length; i++)
            {

                sum = sum + (Convert.ToDouble(a.Substring(i, 1))) * Math.Pow(zhuanjinzhi,a.Length-i-1);
            }
            return sum;
        }
         private double zhuanhuan3(string a, double  shiliu)//把进制为十六进制数转换为十进制
        {
            double sum = 0;
            string c;
            for (int i = 0; i < a.Length; i++)
            {
                if (a.Substring(i, 1) == "A")
                {
                    c = "10";
                }
                else if (a.Substring(i, 1) == "B")
                {
                    c = "11";
                }
                else if (a.Substring(i, 1) == "C")
                {
                    c = "12";
                }
                else if (a.Substring(i, 1) == "D")
                {
                    c = "13";
                }
                else if (a.Substring(i, 1) == "E")
                {
                    c = "14";
                }
                else if (a.Substring(i, 1) == "F")
                {
                    c = "15";
                }
                else
                {
                    c = a.Substring(i, 1);
                }
                sum = sum + Convert.ToDouble(c) * Math.Pow(shiliu,a.Length-i-1);
            }
            return sum;
        }
                        
    }
}