PATH environment variable

Hi all, I am trying to append a certain string to the
PATH environment variable programmatically. I am able to
read what is in the variable using the System.Environment
method GetEnvironmentVariable("path"). However, I don't
know yet how to append strings to the path variable. Any
help is appreciated. Thanks a lot.

There is no managed way to set the environment variable strings.
Rather, you will have to call the SetEnvironmentVariable function through
the P/Invoke layer.

If you are using .NET 2.0, then you can use the static
SetEnvironmentVariable method on the Environment class.

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- mvp@spam.guard.caspershouse.com

<anonymous@discussions.microsoft.com> wrote in message
news:324a01c4c046$9d78f450$a301280a@phx.gbl...[color=blue]
> Hi all, I am trying to append a certain string to the
> PATH environment variable programmatically. I am able to
> read what is in the variable using the System.Environment
> method GetEnvironmentVariable("path"). However, I don't
> know yet how to append strings to the path variable. Any
> help is appreciated. Thanks a lot.[/color]

anonymous@discussions.microsoft.com wrote:[color=blue]
>
> Hi all, I am trying to append a certain string to the
> PATH environment variable programmatically. I am able to
> read what is in the variable using the System.Environment
> method GetEnvironmentVariable("path"). However, I don't
> know yet how to append strings to the path variable. Any
> help is appreciated. Thanks a lot.[/color]

Many ways.

One is to do the following:

string path = @"%PATH%\subfolder\yourapplication.exe";
string expanded = System.Environment.ExpandEnvironmentVairables(path );

Other way:

string expanded = System.Environment.GetEnvironmentVariable("path") +
@"\subfolder\yourapplication.exe";

Thanks for your reply Nicholas. Can you explain how we
can call the SetEnvironmentVariable through the P/Invoke
layer? Thanks a lot in advance.[color=blue]
>-----Original Message-----
> There is no managed way to set the environment[/color]
variable strings.[color=blue]
>Rather, you will have to call the SetEnvironmentVariable[/color]
function through[color=blue]
>the P/Invoke layer.
>
> If you are using .NET 2.0, then you can use the[/color]
static[color=blue]
>SetEnvironmentVariable method on the Environment class.
>
> Hope this helps.
>
>
>--
> - Nicholas Paldino [.NET/C# MVP]
> - mvp@spam.guard.caspershouse.com
>
><anonymous@discussions.microsoft.com> wrote in message
>news:324a01c4c046$9d78f450$a301280a@phx.gbl...[color=green]
>> Hi all, I am trying to append a certain string to the
>> PATH environment variable programmatically. I am able[/color][/color]
to[color=blue][color=green]
>> read what is in the variable using the[/color][/color]
System.Environment[color=blue][color=green]
>> method GetEnvironmentVariable("path"). However, I don't
>> know yet how to append strings to the path variable.[/color][/color]
Any[color=blue][color=green]
>> help is appreciated. Thanks a lot.[/color]
>
>
>.
>[/color]

If you want to change the parent (system) path environment, here is how I did
it:

// Import library used to broadcast a system message that the environment
changed.
[DllImport("user32.dll", SetLastError=true, CharSet=CharSet.Auto)]
static extern IntPtr SendMessageTimeout(IntPtr hWnd, uint Msg,
UIntPtr wParam, string lParam, SendMessageTimeoutFlags fuFlags,
uint uTimeout, out UIntPtr lpdwResult);

public static string RegKey = @"System\CurrentControlSet\Control\Session
Manager\Environment";

public static string NewPathForFolder = "d:\bin";


public enum SendMessageTimeoutFlags:uint
{
SMTO_NORMAL= 0x0000
, SMTO_BLOCK = 0x0001
, SMTO_ABORTIFHUNG = 0x0002
, SMTO_NOTIMEOUTIFNOTHUNG = 0x0008
}



private static void SetEnvironmentPath()
{
// Update registry with environment variable path
RegistryKey key;
key = Registry.LocalMachine.OpenSubKey(RegKey,true);
string path = (String)key.GetValue("Path");
string TestPath = NewPathForFolder;
int a = path.IndexOf(TestPath,1);
if (a == -1)
{
path += ";" + NewFolderForPath;
key.SetValue("Path", path);

//Notify all windows that User Environment variables are changed
IntPtr HWND_BROADCAST = (IntPtr) 0xffff;
const UInt32 WM_SETTINGCHANGE = 0x001A;
UIntPtr result;
IntPtr settingResult = SendMessageTimeout(HWND_BROADCAST,
WM_SETTINGCHANGE,
(UIntPtr)0,
"Environment",
SendMessageTimeoutFlags.SMTO_NORMAL,
10000,
out result);
}
}








"anonymous@discussions.microsoft.com" wrote:
[color=blue]
> Hi all, I am trying to append a certain string to the
> PATH environment variable programmatically. I am able to
> read what is in the variable using the System.Environment
> method GetEnvironmentVariable("path"). However, I don't
> know yet how to append strings to the path variable. Any
> help is appreciated. Thanks a lot.
>[/color]