// Pseudo-name format so GetUserNameEx can return the DNS domain name to

    public static String GetUsernameBySessionId(int sessionId)

public static extern int GetUserNameEx (ExtendedNameFormat nameFormat,

Declare Function GetUserNameEx Lib "secur32.dll" (nameFormat As Integer, _

      public static extern int GetUserNameEx (int nameFormat, StringBuilder userName, ref int userNameSize);

     if(0 != GetUserNameEx((int)EXTENDED_NAME_FORMAT.NameSamCompatible, userName, ref userNameSize))

  Declare Function GetUserNameExA Lib "secur32.dll" (ByVal nameFormat As Integer, _

' GetUserNameExA for ANSI

' GetUserNameExW for UNICODE

    Public Function GetUserName() As String

    If GetUserNameExA(EXTENDED_NAME_FORMAT.NameSamCompatible, UserName, userNameSize) <> 0 Then

  // Pseudo-name format so GetUserNameEx can return the DNS domain name to

        UInt32 GetUserName([MarshalAs(UnmanagedType.BStr)][Out] out string sUserName);

static extern bool GetUserName(System.Text.StringBuilder sb, ref Int32 length);

<DllImport("advapi32.dll", EntryPoint:="GetUserNameW", SetLastError:=True)> _

Public Function GetUserName(<MarshalAs(UnmanagedType.LPTSTR)>sb As System.Text.StringBuilder, _

Declare Function GetUserName Lib "advapi32.dll" Alias "GetUserNameA" (ByVal lpBuffer As String, ByRef nMax As Integer) As Boolean

namespace GetUserNameExample

        static extern bool GetUserName(StringBuilder lpBuffer, ref int nSize);    

            GetUserName(Buffer, ref nSize);

Namespace GetUserNameExample

        <DllImport("advapi32.dll", EntryPoint:="GetUserNameA", SetLastError:=True)> _

        Public Function GetUserName(<MarshalAs(UnamagedType.LPTSTR)>System.Text.StringBuilder sb, _

            GetUserName(Buffer, nSize)

rc = GetUserName(xstr,max)

public static extern bool GetUserName(System.Text.StringBuilder sb, ref Int32 length);

[Advapi32.util]::GetUserName($str,[ref]$size) |Out-Null