GetEnvironmentVariable() and SetEnvironmentVariable() for PATH Variable

Question

I want to extend the current PATH variable with a C# program. Here I have several problems:

1. Using GetEnvironmentVariable(\"PATH\", EnvironmentVariable

Answer 1

You could try this mix. It gets the Path variables from the registry, and adds the "NewPathEntry" to Path, if not already there.

static void Main(string[] args)
    {
        string NewPathEntry = @"%temp%\data";
        string NewPath = "";
        bool MustUpdate = true;
        string RegKeyName = @"SYSTEM\CurrentControlSet\Control\Session Manager\Environment";
        string path = (string)Microsoft.Win32.Registry.LocalMachine.OpenSubKey(RegKeyName).GetValue
            ("Path", "", Microsoft.Win32.RegistryValueOptions.DoNotExpandEnvironmentNames);
        string[] paths = path.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
        foreach (string subPath in paths)
        {
            NewPath += subPath + ";";
            if (subPath.ToLower() == NewPathEntry.ToLower())
            {
                MustUpdate = false;
            }
        }
        if (MustUpdate == true)
        {
            Environment.SetEnvironmentVariable("Path", NewPath + NewPathEntry, EnvironmentVariableTarget.Machine);
        }
    }