C# Signature:

[DllImport("secur32.dll", SetLastError=true)]
static extern int TranslateName(string accountName, int nameFormat,
        int desiredFormat, StringBuilder translatedName, ref int userNameSize);

VB Signature:

Declare Function TranslateName Lib "secur32.dll" (TODO) As TODO

User-Defined Types:

None.

Alternative Managed API:

Do you know one? Please contribute it!

Notes:

This may be required to obtain the UPN (or other format) of a user's credentials. Minimum supported OS is Windows 2000. Full documentation of the native API is available from http://msdn.microsoft.com/en-us/library/ms725484(VS.85).aspx.

Tips & Tricks:

Please add some!

Sample Code:

  public class Sample
  {
      enum EXTENDED_NAME_FORMAT
      {
          NameUnknown = 0,
          NameFullyQualifiedDN = 1,
          NameSamCompatible = 2,
          NameDisplay = 3,
          NameUniqueId = 6,
          NameCanonical = 7,
          NameUserPrincipal = 8,
          NameCanonicalEx = 9,
          NameServicePrincipal = 10,
          NameDnsDomain = 12
      }

      [DllImport("secur32.dll", SetLastError=true)]
      public static extern int TranslateName(string accountName, int nameFormat,
        int desiredFormat, StringBuilder translatedName, ref int userNameSize);

      public string GetTranslatedName(string domain, string user)
      {
          string samCompatibleName = domain.ToUpper() + "\\" + username;
          StringBuilder translatedName = new StringBuilder(1024);
          int userNameSize = translatedName.Capacity;

          if (0 != TranslateName(samCompatibleName,
              (int)EXTENDED_NAME_FORMAT.NameSamCompatible,
              (int)EXTENDED_NAME_FORMAT.NameUserPrincipal,
              translatedName, ref userNameSize))
          {
              // Make sure we got a UPN out as expected
              if (translatedName.ToString().Split('@').Length == 2)
              {
                  return translatedName.ToString();
              }
          }

          return null;
       }
  }