C#操作注册表,设置系统环境变量

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Win32;
using System.Runtime.InteropServices;

namespace 设置系统环境变量
{
 class SysEnvironment
 {
 /// <summary>
 /// 获取系统环境变量
 /// </summary>
 /// <param name="name">输入HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment
 /// 下key的对应的字符串</param>
 /// <returns>Key对应的字符串</returns>
 public static string GetSysEnvironmentByName(string key)
 {
 string result = string.Empty;
 try
 {
                result = OpenSysEnvironment().GetValue(key).ToString();
 }
 catch (Exception)
 {

 return result;
 }
 return result;
 }

 /// <summary>
 /// 获得RegistryKey,值为
 /// HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment
 /// </summary>
 /// <returns></returns>
 public static RegistryKey OpenSysEnvironment()
 {
 RegistryKey regLocalMachine = Registry.LocalMachine;

 //打开HKEY_LOCAL_MACHINE下的SYSTEM,true表示具有写权限 
 //RegistryKey regSystem = regLocalMachine.OpenSubKey("System", true);
 //RegistryKey regControlSet = regSystem.OpenSubKey("CurrentControlSet", true).OpenSubKey("Control",true).OpenSubKey("Session Manager",true);
 RegistryKey regEnvironment = regLocalMachine.OpenSubKey(@"System\CurrentControlSet\Control\Session Manager\Environment", true);
 return regEnvironment;
 }

 /// <summary>
 /// 设置系统环境变量
 /// </summary>
 /// <param name="name">变量名</param>
 /// <param name="strValue">值</param>
 /// <param name="i">用来表示在路径首添加,还是在路径末尾添加</param>
 public static string SetSysEnvironment(string key, string strValue)
 {
 string pathList = null;

 if (CheckSysEnvironmentExist(key) == false)
 {
 //如果环境变量不存在,直接key-value添加就可
 OpenSysEnvironment().SetValue(key, strValue);
 return "已成功将所给key的环境变量设为value!";
 }
 else
 {
 //如果环境变量存在,需要首先检查value是否已经包含在key所对应的string中,
 //如果不包含在其中,就添加,否则,直接返回就可
                pathList = GetSysEnvironmentByName(key);
 if (pathList.Contains(strValue))
 {
 return "所给key的环境变量已包含value!";//已设置过,不用再次设置
 }
 if (!pathList.EndsWith(";"))
 {
 OpenSysEnvironment().SetValue(key, pathList + ";");
                    pathList = GetSysEnvironmentByName(key);
 }
 else
 {
 OpenSysEnvironment().SetValue(key, pathList + strValue);
 return "已成功在环境变量尾追加所给变量!";
 }
 }
 }

 /// <summary>
 /// 检测系统环境变量是否存在
 /// </summary>
 /// <param name="name">要修改path的Key</param>
 /// <returns></returns>
 public static Boolean CheckSysEnvironmentExist(string key)
 {
 if (!string.IsNullOrEmpty(GetSysEnvironmentByName(key)))
 {
 return true;
 }
 else
 {
 return false;
 }
 }
 }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 设置系统环境变量
{
 class Program
 {
 static void Main(string[] args)
 {
 Console.WriteLine(@"请输入您要输入的键值对,用空格分割,如 Path C:\Go");
 string keyValue = Console.ReadLine();
 while (keyValue != "z")
 {
 string[] result = keyValue.Split(new char[]{' '},StringSplitOptions.RemoveEmptyEntries);
 string key = result[0];//这几行主要是处理输入路径中空格的情况,输入的是D:\Program Files\Siemens\NX 9.0\UGII,也不会因为空格而变成 D:\Program
 string value = keyValue.Trim().Remove(0, key.Length).Trim(' ');
 Console.WriteLine("key:{0} \t value:{1}", key, value);
 Console.WriteLine(SysEnvironment.SetSysEnvironment(key, value));
 Console.WriteLine("请输入下一键值对,按z加上回车结束程序");
                keyValue = Console.ReadLine();
 }
 Console.ReadKey();
 }
 }
}