using System;
using System.Text;
using System.Runtime.InteropServices;
 
namespace WinAPI.SearchPath
{
    class Class1
    {
        /*
        EntryPoint="PathFindOnPathA" means that the function expects 
        strings in one byte per character format. PathFindOnPathW must 
        be used otherwise.
 
        System.Text.StringBuilder Class represents a string-like object.
        Its value can be modified once it has been created 
        by appending, removing, replacing, or inserting characters. 
        In the code below the upper limit of 260 characters is set 
        for the new instance of the StringBuilder.
 
        The last member of dirs, the array that stores directory names,
        must be null. Omitting this, triggers an exception, 
        System.NullReferenceException, if the file name is not found.
         */
 
        const int MAX_PATH = 260;
 
        [STAThread]
        static void Main()
        {
            StringBuilder f =  //file to be searched
                new StringBuilder("test.txt", MAX_PATH);
 
            //directories to be searched first
            string[] dirs = {"c:\\dir1",
                "c:\\dir2", "c:\\documents\\dir1", null};
 
            Console.WriteLine(PathFindOnPath(f, dirs) ?
                f.ToString() : "File not found");
 
            Console.ReadLine();
        }
 
        [DllImport("shlwapi.dll", EntryPoint="PathFindOnPathA") ]
        static extern bool PathFindOnPath(System.Text.StringBuilder pszFile,
            string[] ppszOtherDirs);
 
    }
}