这是一个示例,通过编程方式编辑注册表来永久更新用户PATH变量:
// Admin Permission not-required:
// HKCU\Environment\Path
// Admin Permission required:
// HKLM\SYSTEM\CurrentControlSet\Control
// \Session Manager\Environment\Path
public static void UserPathAppend(string path, int verbose=1) {
string oldpath = UserPathGet();
List<string> newpathlist = oldpath.Split(';').ToList();
newpathlist.Add(path);
string newpath = String.Join(";", newpathlist.ToArray());
UserPathSet(newpath);
UpdateEnvPath();
if (verbose!=0) {
System.Windows.MessageBox.Show(
"PATH APPEND:\n\n"
+ path + "\n\n"
+ "OLD HKCU PATH:\n\n"
+ oldpath + "\n\n"
+ "NEW HKCU PATH:\n\n"
+ newpath + "\n\n"
+ "REGISTRY KEY MODIFIED:\n\n"
+ "HKCU\\Environment\\Path\n\n"
+ "NOTE:\n\n"
+ "'Command Path' is a concat of 'HKLM Path' & 'HKCU Path'.\n",
"Updated Current User Path Environment Variable"
);
}
}
public static void UserPathPrepend(string path, int verbose=1) {
string oldpath = UserPathGet();
List<string> newpathlist = oldpath.Split(';').ToList();
newpathlist.Insert(0, path);
string newpath = String.Join(";", newpathlist.ToArray());
UserPathSet(newpath);
UpdateEnvPath();
if (verbose != 0) {
System.Windows.MessageBox.Show(
"PATH PREPEND:\n\n"
+ path + "\n\n"
+ "OLD HKCU PATH:\n\n"
+ oldpath + "\n\n"
+ "NEW HKCU PATH:\n\n"
+ newpath + "\n\n"
+ "REGISTRY KEY MODIFIED:\n\n"
+ "HKCU\\Environment\\Path\n\n"
+ "NOTE:\n\n"
+ "'Command Path' is a concat of 'HKLM Path' & 'HKCU Path'.\n",
"Updated Current User Path Environment Variable"
);
}
}
public static string UserPathGet()
{
// Reads Registry Path "HKCU\Environment\Path"
string subKey = "Environment";
Microsoft.Win32.RegistryKey sk = Microsoft.Win32.Registry.CurrentUser.OpenSubKey(subKey);
if (sk == null)
return null;
else
return sk.GetValue("Path").ToString();
}
public static void UserPathSet(string newpath)
{
// Writes Registry Path "HKCU\Environment\Path"
string subKey = "Environment";
Microsoft.Win32.RegistryKey sk1 = Microsoft.Win32.Registry.CurrentUser.CreateSubKey(subKey);
sk1.SetValue("Path", newpath);
}
//===========================================================
// Private: This part required if you don't want to logout
// and login again to see Path Variable update
//===========================================================
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
private static extern IntPtr SendMessageTimeout(IntPtr hWnd,
uint Msg, UIntPtr wParam, string lParam,
SendMessageTimeoutFlags fuFlags,
uint uTimeout, out UIntPtr lpdwResult);
private enum SendMessageTimeoutFlags : uint
{
SMTO_NORMAL = 0x0, SMTO_BLOCK = 0x1,
SMTO_ABORTIFHUNG = 0x2, SMTO_NOTIMEOUTIFNOTHUNG = 0x8
}
private static void UpdateEnvPath() {
// SEE: https://support.microsoft.com/en-us/help/104011/how-to-propagate-environment-variables-to-the-system
// Need to send WM_SETTINGCHANGE Message to
// propagage changes to Path env from registry
IntPtr HWND_BROADCAST = (IntPtr)0xffff;
const UInt32 WM_SETTINGCHANGE = 0x001A;
UIntPtr result;
IntPtr settingResult
= SendMessageTimeout(HWND_BROADCAST,
WM_SETTINGCHANGE, (UIntPtr)0,
"Environment",
SendMessageTimeoutFlags.SMTO_ABORTIFHUNG,
5000, out result);
}