C# Signature:

[DllImport("shlwapi.dll", CharSet=CharSet.Auto, SetLastError=false)]
static extern bool PathFindOnPath([In, Out] StringBuilder pszFile, [In] String [] ppszOtherDirs);

VB Signature:

Declare Function PathFindOnPath Lib "shlwapi.dll" (TODO) As TODO

Notes:

Make sure pszFile has enough space for MAX_PATH characters.

ppszOtherDirs is a list of specific directories to search first. It can be null if you want to search only the PATH.

If you pass some additional directories in ppszOtherDirs, be sure to add an extra null to the array (otherwise, it will crash in case the file is not found).

This function does not include the current dir or the application launch dir in its search.

Tips & Tricks:

None.

Sample Code:

int MAX_PATH=260;

StringBuilder sb = new StringBuilder("somefile.dll", MAX_PATH);
bool found = PathFindOnPath(sb, new String [] {"c:\\test", "c:\\junk", null} );
if (found)
{
    Console.WriteLine("File was found at: " + sb.ToString());
}
else
{
    Console.WriteLine("File was not found");
}

Alternative Managed API:

None that I could find.