获取Sql服务器列表

怎么实现这个功能大家肯定早都知道了，放上来是给自己留个备份
使用：

private void button1_Click_1(object sender, System.EventArgs e)
...{
 string[] servers = DBGrep.SqlLocator.GetServers();
 foreach ( string s in servers )
 ...{
  this.listBox1.Items.Add(s);
 }
}

类的代码

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

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;
  }
 }
}