Occasionally you might have the need to convert a mapped drive letter to a UNC or network path. For example, a drive letter such as  “Z” might be mapped to a network share:

In this example, the “Z” drive is mapped to a “Personal” folder on a server named “Home”.

If you want to store for example a UNC path to a file rather than a drive letter, you’ll need to convert the “Z” drive to the corresponding UNC root path. Here’s the C# code I wrote to do this:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.IO;

namespace WiredPrairie.Samples
{
    public static class Pathing
    {
        [DllImport("mpr.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        public static extern int WNetGetConnection(
            [MarshalAs(UnmanagedType.LPTStr)] string localName, 
            [MarshalAs(UnmanagedType.LPTStr)] StringBuilder remoteName, 
            ref int length);
        /// <summary>
        /// Given a path, returns the UNC path or the original. (No exceptions
        /// are raised by this function directly). For example, "P:\2008-02-29"
        /// might return: "\\networkserver\Shares\Photos\2008-02-09"
        /// </summary>
        /// <param name="originalPath">The path to convert to a UNC Path</param>
        /// <returns>A UNC path. If a network drive letter is specified, the
        /// drive letter is converted to a UNC or network path. If the 
        /// originalPath cannot be converted, it is returned unchanged.</returns>
        public static string GetUNCPath(string originalPath)
        {
            StringBuilder sb = new StringBuilder(512);
            int size = sb.Capacity;

            // look for the {LETTER}: combination ...
            if (originalPath.Length > 2 && originalPath[1] == ':')
            {
                // don't use char.IsLetter here - as that can be misleading
                // the only valid drive letters are a-z && A-Z.
                char c = originalPath[0];
                if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
                {
                    int error = WNetGetConnection(originalPath.Substring(0, 2), 
                        sb, ref size);
                    if (error == 0)
                    {                        
                        DirectoryInfo dir = new DirectoryInfo(originalPath);

                        string path = Path.GetFullPath(originalPath)
                            .Substring(Path.GetPathRoot(originalPath).Length);
                        return Path.Combine(sb.ToString().TrimEnd(), path);
                    }
                }
            }
            
            return originalPath;
        }
    }
}

All of the magic takes place in a Windows API function call, WNetGetConnection.

I’m using this function so that I can verify that given two file names, I can be assured that they are pointing to the same physical location. (Is “Z:\Backups\Backup1.zip” the same as “\\home\Personal\Backups\Backup1.zip”).

Adobe made a handful of announcements early this morning:

• A new Open Source portal
• Flex 3 is ready and final. Flex Builder 3, which you’ll want if you are serious about building Flex applications, is US$249.
• Adobe AIR is released

The Flex team’s blog announcement has more details and a lot of links to get you started.

Is it just me, or are none of the demo applications very compelling?

The biggest change from "yesterday" is that it might be easier today to write a cross-platform application — as long as AIR/Flex supports what you want to do outside of the browser. I’d like Adobe to offer the "Express" edition of Flex Builder so I can build things for free, just like Microsoft does with Visual Studio.

Are you excited about this "AIR"? (Or Flex?)