如何在 C# 中设置系统环境变量?

问题描述

我试图在我的应用程序中设置一个系统环境变量，但得到一个 SecurityException.我测试了我在谷歌中找到的所有东西 - 没有成功.这是我的代码(注意，我是我的电脑的管理员并以管理员身份运行 VS2012):

I'm trying to set a system environment variable in my application, but get an SecurityException. I tested everything I found in google - without success.Here is my code (note, that I'm administrator of my pc and run VS2012 as admin):

尝试 1

new EnvironmentPermission(EnvironmentPermissionAccess.Write, "TEST1").Demand();
Environment.SetEnvironmentVariable("TEST1", "MyTest", EnvironmentVariableTarget.Machine);

尝试 2

new EnvironmentPermission(EnvironmentPermissionAccess.Write, "TEST1").Demand();

using (var envKey = Registry.LocalMachine.OpenSubKey(@"SYSTEMCurrentControlSetControlSession ManagerEnvironment", true))
{

  Contract.Assert(envKey != null, @"HKLMSystemCurrentControlSetControlSession ManagerEnvironment is missing!");
  envKey.SetValue("TEST1", "TestValue");
}

尝试 3我还尝试让我的应用具有管理员权限.

您还有其他建议吗?

推荐答案

文档告诉你如何做到这一点.

The documentation tells you how to do this.

调用 SetEnvironmentVariable 对系统环境变量没有影响.要以编程方式添加或修改系统环境变量，请将它们添加到 HKEY_LOCAL_MACHINESystemCurrentControlSetControlSession ManagerEnvironment 注册表项，然后使用 广播 WM_SETTINGCHANGE 消息>lParam 设置为字符串 "Environment".这允许应用程序(例如 shell)获取您的更新.

因此，您需要写入您已经尝试写入的注册表设置.然后广播 WM_SETTINGCHANGE 消息，如上所述.您需要以提升的权限运行才能成功.

So, you need to write to the registry setting that you are already attempting to write to. And then broadcast a WM_SETTINGCHANGE message as detailed above. You will need to be running with elevated rights in order for this to succeed.

一些示例代码:

using Microsoft.Win32;
using System;
using System.Diagnostics.Contracts;
using System.Runtime.InteropServices;

namespace ConsoleApplication1
{
    class Program
    {
        const int HWND_BROADCAST = 0xffff;
        const uint WM_SETTINGCHANGE = 0x001a;

        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool SendNotifyMessage(IntPtr hWnd, uint Msg,
            UIntPtr wParam, string lParam);

        static void Main(string[] args)
        {
            using (var envKey = Registry.LocalMachine.OpenSubKey(
                @"SYSTEMCurrentControlSetControlSession ManagerEnvironment",
                true))
            {
                Contract.Assert(envKey != null, @"registry key is missing!");
                envKey.SetValue("TEST1", "TestValue");
                SendNotifyMessage((IntPtr)HWND_BROADCAST, WM_SETTINGCHANGE,
                    (UIntPtr)0, "Environment");
            }
        }
    }
}

但是，虽然此代码确实有效，但 .net 框架提供了更简单地执行相同任务的功能.

However, whilst this code does work, the .net framework provides functionality to perform the same task much more simply.

Environment.SetEnvironmentVariable("TEST1", "TestValue",
    EnvironmentVariableTarget.Machine);

三个参数 Environment.SetEnvironmentVariable 的 文档 重载说:

The documentation for the three argument Environment.SetEnvironmentVariable overload says:

如果目标是 EnvironmentVariableTarget.Machine，则环境变量存储在本地计算机注册表的 HKEY_LOCAL_MACHINESYSTEMControlSet001ControlSession ManagerEnvironment 键中.它也被复制到文件资源管理器的所有实例中.然后，从文件资源管理器启动的任何新进程都会继承环境变量.

如果目标是用户或机器，则通过 Windows WM_SETTINGCHANGE 消息通知其他应用程序设置操作.

If target is User or Machine, other applications are notified of the set operation by a Windows WM_SETTINGCHANGE message.

这篇关于如何在 C# 中设置系统环境变量?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！