private static void SetEnvironmentVariable(string name, string value, SetVariableFlags flag,
EnvironmentVariableTarget target)
{
var current = Environment.GetEnvironmentVariable(name, target);
if (current != null)
{
if (flag.HasFlag(SetVariableFlags.Append))
{
if (current.Split(';').Contains(value, true))
{
throw new ValueExistsException();
}
Environment.SetEnvironmentVariable(name, string.Join(";", current, value), target);
}
else if (flag.HasFlag(SetVariableFlags.Overwrite))
{
Environment.SetEnvironmentVariable(name, value, target);
}
else
{
throw new InvalidOperationException("The specified variable already exists.");
}
}
else
{
Environment.SetEnvironmentVariable(name, value, target);
}
const int timeoutMilliseconds = 15000;
var result = SendMessageTimeout(
HWND_BROADCAST,
WM_SETTINGCHANGE,
UIntPtr.Zero,
Marshal.StringToHGlobalUni("Environment"),
SMTO_ABORTIFHUNG,
timeoutMilliseconds,
out _);
if (result != IntPtr.Zero)
{
return;
}
var win32Err = Marshal.GetLastWin32Error();
if ((ulong)win32Err == ERROR_TIMEOUT)
{
throw new TimeoutException("The SendMessage operation timed out.");
}
throw new Win32Exception(win32Err);
}
public static void SetSystemVariable(string name, string value, SetVariableFlags flag)
{
SetEnvironmentVariable(name, value, flag, EnvironmentVariableTarget.Machine);
}
public static void SetUserVariable(string name, string value, SetVariableFlags flag)
{
SetEnvironmentVariable(name, value, flag, EnvironmentVariableTarget.User);
}