How To Get SQL Instance Using C#

hello guys this a simple tutorial that will give you the list of SQL servers available on your lan . ok lets begin making this just open c# and make a new project and name it whatever and after form finished loading add a button and change the text  to refresh and add combobox and at last add a label to make the ui beautiful now  add a class and name it getsql.cs

ok now you will see the class in the side bar ok now go to getsql.cs and add this codes

using System;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

//Author : Mohamed Shimran
//Blog : http://www.ultimateprogrammingtutorials.blogspot.com

namespace DBGrep
{
 public class SqlLocator
 {
  [DllImport("odbc32.dll")]
  private static extern short SQLAllocHandle(short hType, IntPtr inputHandle, out IntPtr outputHandle);
  [DllImport("odbc32.dll")]
  private static extern short SQLSetEnvAttr(IntPtr henv, int attribute, IntPtr valuePtr, int strLength);
  [DllImport("odbc32.dll")]
  private static extern short SQLFreeHandle(short hType, IntPtr handle); 
  [DllImport("odbc32.dll",CharSet=CharSet.Ansi)]
  private static extern short SQLBrowseConnect(IntPtr hconn, StringBuilder inString, 
   short inStringLength, StringBuilder outString, short outStringLength,
   out short outLengthNeeded);

  private const short SQL_HANDLE_ENV = 1;
  private const short SQL_HANDLE_DBC = 2;
  private const int SQL_ATTR_ODBC_VERSION = 200;
  private const int SQL_OV_ODBC3 = 3;
  private const short SQL_SUCCESS = 0;
  
  private const short SQL_NEED_DATA = 99;
  private const short DEFAULT_RESULT_SIZE = 1024;
  private const string SQL_DRIVER_STR = "DRIVER=SQL SERVER";
 
  private SqlLocator(){}

  public static string[] GetServers()
  {
   string[] retval = null;
   string txt = string.Empty;
   IntPtr henv = IntPtr.Zero;
   IntPtr hconn = IntPtr.Zero;
   StringBuilder inString = new StringBuilder(SQL_DRIVER_STR);
   StringBuilder outString = new StringBuilder(DEFAULT_RESULT_SIZE);
   short inStringLength = (short) inString.Length;
   short lenNeeded = 0;

   try
   {
    if (SQL_SUCCESS == SQLAllocHandle(SQL_HANDLE_ENV, henv, out henv))
    {
     if (SQL_SUCCESS == SQLSetEnvAttr(henv,SQL_ATTR_ODBC_VERSION,(IntPtr)SQL_OV_ODBC3,0))
     {
      if (SQL_SUCCESS == SQLAllocHandle(SQL_HANDLE_DBC, henv, out hconn))
      {
       if (SQL_NEED_DATA ==  SQLBrowseConnect(hconn, inString, inStringLength, outString, 
        DEFAULT_RESULT_SIZE, out lenNeeded))
       {
        if (DEFAULT_RESULT_SIZE < lenNeeded)
        {
         outString.Capacity = lenNeeded;
         if (SQL_NEED_DATA != SQLBrowseConnect(hconn, inString, inStringLength, outString, 
          lenNeeded,out lenNeeded))
         {
          throw new ApplicationException("Unabled to aquire SQL Servers from ODBC driver.");
         } 
        }
        txt = outString.ToString();
        int start = txt.IndexOf("{") + 1;
        int len = txt.IndexOf("}") - start;
        if ((start > 0) && (len > 0))
        {
         txt = txt.Substring(start,len);
        }
        else
        {
         txt = string.Empty;
        }
       }      
      }
     }
    }
   }
   catch (Exception ex)
   {
    //Throw away any error if we are not in debug mode
#if (DEBUG)
    MessageBox.Show(ex.Message,"Acquire SQL Servier List Error");
#endif 
    txt = string.Empty;
   }
   finally
   {
    if (hconn != IntPtr.Zero)
    {
     SQLFreeHandle(SQL_HANDLE_DBC,hconn);
    }
    if (henv != IntPtr.Zero)
    {
     SQLFreeHandle(SQL_HANDLE_ENV,hconn);
    }
   }
 
   if (txt.Length > 0)
   {
    retval = txt.Split(",".ToCharArray());
   }

   return retval;
  }
 }
}

now check if your form have this look to make it look good

now double click your form and add this codes:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

//Author : Mohamed Shimran
//Blog : http://www.ultimateprogrammingtutorials.blogspot.com

namespace GetSQLInstance
{
    public partial class Form1 : Form
    {
        public Form1()
        {

            InitializeComponent();


        }
  
        private void Form1_Load(object sender, EventArgs e)
        {
            button1_Click(sender, e);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string[] theAvailableSqlServers = DBGrep.SqlLocator.GetServers();
            if (theAvailableSqlServers != null)
            {
                comboBox1.DataSource = theAvailableSqlServers;
            }
            else
            {
                MessageBox.Show("No SQL servers found.");
            }
        }
    }
}

now all done its time to test the application when you run the program if you get a message like this

you dont have any SQL servers on your lan