How to get Windows’ Serial Number and Windows Logon User Name in .NET

By using the namespace System.Management, we can easily retrieve the serial number of your Windows OS and windows logon user name.

First of all, you need to add a reference of System.Management into your application. To add a reference into your .NET application, you can right-click on References in the solution explorer and select Add Reference.


From the Add References dialog box, select System.Management and click OK.


The sample codes below written in both C# and VB .NET show you how to read the Windows’ serial number and logon user name.

C# .NET
using System.Management;

public static string getSerialNumber() {
  string _serialNo = string.Empty;

  ManagementObjectSearcher objMOS = new ManagementObjectSearcher("Select * from Win32_OperatingSystem");
  ManagementObjectCollection objMOC;

  objMOC = objMOS.Get();

  foreach (ManagementObject objMO in objMOC) {
    _serialNo = objMO["SerialNumber"].ToString();
  }

  return _serialNo;
}

public static string getlogonUser(){
  string _user = string.Empty;

  ManagementObjectSearcher objMOS = new ManagementObjectSearcher("SELECT * FROM Win32_ComputerSystem");
  ManagementObjectCollection objMOC;

  objMOC = objMOS.Get();

  foreach (ManagementObject objMO in objMOC) {
    _user = objMO ["UserName"].ToString();
  }

  return _user;
}


VB .NET
Imports System.Management

Public Shared Function getSerialNumber() As String
  Dim _serialNo As String = String.Empty

  Dim objMOS As New ManagementObjectSearcher("Select * from Win32_OperatingSystem")
  Dim objMOC As ManagementObjectCollection

  objMOC = objMOS.Get

  For Each objMO As ManagementObject In objMOC
    _serialNo = objMO("SerialNumber").ToString()
  Next

  Return _serialNo
End Function

Public Shared Function getlogonUser() As String
  Dim _user As String = String.Empty

  Dim objMOS As New ManagementObjectSearcher("SELECT * FROM Win32_ComputerSystem")
  Dim objMOC As ManagementObjectCollection

  objMOC = objMOS.Get

  For Each objMO As ManagementObject In objMOC
    _user = objMO("UserName").ToString()
  Next

  Return _user
End Function

Cheers.