private void button1_Click(object sender, EventArgs e)

        {

            try

            {

                //OdbcConnection conn = new OdbcConnection();

                //conn.ConnectionString =

                //         "ODBC;" +

                //         "Driver={Sybase SQL Anywhere 5.0};" +

                //         "DefaultDir=c:\myfolder\;" +

                //         "Dbf=c:\mypath\dbname.db;" +

                //         "Uid=UserName;" +

                //         "Pwd=Secret;" +

                //         "Dsn="""";";     // Must be included!

                //conn.Open();   geovindu

                connectionString = "DSN=geovindu;UID=dba;PWD=sql;"; //Data Source=sademo

                using (OdbcConnection connection = new OdbcConnection(connectionString))

                {

                    connection.Open();

                    DataTable dt = new DataTable();// connection.GetSchema();

                    DataSet ds = new DataSet();

                   OdbcDataAdapter da = new OdbcDataAdapter("SELECT * FROM employee", connection);

                   da.Fill(ds);

                   dt = ds.Tables[0];

                    // Do work here.

                   this.dataGridView1.DataSource = dt;

                }

            }

            catch (OdbcException ex)

            {

                MessageBox.Show(ex.Message.ToString());

            }

        }

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using Microsoft.Win32;

using System.Data.Odbc;

using System.Data.SqlClient;

/*

https://msdn.microsoft.com/en-us/library/system.data.odbc.odbcconnection.connectionstring%28v=vs.110%29.aspx

 *

 * "Driver={SQL Server};Server=(local);Trusted_Connection=Yes;Database=AdventureWorks;"

"Driver={Microsoft ODBC for Oracle};Server=ORACLE8i7;Persist Security Info=False;Trusted_Connection=Yes"

"Driver={Microsoft Access Driver (*.mdb)};DBQ=c:\bin\Northwind.mdb"

"Driver={Microsoft Excel Driver (*.xls)};DBQ=c:\bin\book1.xls"

"Driver={Microsoft Text Driver (*.txt; *.csv)};DBQ=c:\bin"

"DSN=dsnname"

 *

 DSN类型有以下三种：

用户DSN:该数据源只能对建立数据源的用户可见.

ODBC用户数据源存贮了如何与指定数据库提供者连接的信息.只对当前用户可见,而且只能用于当前机器上.这里的当前机器是只这个配置只对当前的机器有效,而不是说只能配置本机上的数据库.它可以配置局域网中另一台机器上的数据库.

系统DSN:该数据源对当前机器上所有的用户可见.

ODBC系统数据源存贮了如何指定数据库提供者连接的信息，系统数据对当前机器上的所有用户都是可见的,包括NT服务.也就是说在这里配置的数据源,只要是这台机器的用户都可以访问 .

文件DSN:该数据源对安装了相同驱动的用户可见

用户DSN只被用户直接使用,它只能用于当前机器中,ASP不能使用它.系统DSN允许所有的用户登陆到特定服务器上去访问数据库,任何具有权限有用户都可以访问系统DSN.在WEB应用程序中访问数据库时,通常都是建立系统DSN. 文件DSN将信息存储在后缀为.dsn的文本文件中,优点是便于移动.

用户DSN只是针对当前用户或者特定用户；系统DSN是底层的，针对全部用户。一般没有特殊情况时，建议使用使用系统DSN，通用性好。

 */

namespace SQLanyWhereDemo

{

    /// <summary>

    /// 塗聚文 涂聚文

    /// </summary>

    public partial class Form4 : Form

    {

        RegistryKey regRootKey;

        RegistryKey regSubKey;

        /// <summary>

        ///

        /// </summary>

        public Form4()

        {

            InitializeComponent();

        }

        /// <summary>

        ///

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void Form4_Load(object sender, EventArgs e)

        {

            List<string> dsnList = new List<string>();

            ///定义Root指向注册表HKEY_LOCAL_MACHINE节点，

            ///如果是需要获取用户DSN则需要使用 Registry.CurrentUser;

            regRootKey = Registry.LocalMachine;

            ///定义注册表子Path

            string strRegPath = @"SOFTWARE\ODBC\ODBC.INI\ODBC Data Sources";

            regSubKey = regRootKey.OpenSubKey(strRegPath);

            string[] strDSNList = regSubKey.GetValueNames();

            foreach (string s in strDSNList)

            {

                dsnList.Add(s);

            }

            ///关闭

            regSubKey.Close();

            regRootKey.Close();

            this.comboBox1.DataSource = dsnList;

        }

        /// <summary>

        /// is_archive

        /// is_archive

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void button1_Click(object sender, EventArgs e)

        {

            try

            {

                string conStr = "DSN=LocalServer";

                SqlConnection mCn = new SqlConnection(conStr);

                mCn.Open();

            }

            catch (SqlException ex)

            {

                MessageBox.Show(ex.Message.ToString());

            }

        }

        /// <summary>

        ///

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void button2_Click(object sender, EventArgs e)

        {

            try

            {

                string conStr = "DSN=geovindu";//uid=dba;PWD=geovindu" Driver={Sybase SQL Anywhere 5.0};

                OdbcConnection conn = new OdbcConnection(conStr);

                conn.Open();

                //OdbcConnection mCn = new OdbcConnection();

                //mCn.ConnectionString = "DSN=" + this.comboBox1.Text.Trim();

                //mCn.Open();

            }

            catch (OdbcException ex)

            {

                MessageBox.Show(ex.Message.ToString());

            }

        }

        private const string ODBC_INI_REG_PATH = "SOFTWARE\\ODBC\\ODBC.INI\\";

        private const string ODBCINST_INI_REG_PATH = "SOFTWARE\\ODBC\\ODBCINST.INI\\";

        /// <summary>

        /// Creates a new System-DSN entry with the specified values. If the DSN exists, the values are updated.

        /// </summary>

        /// <param name="dsnName">Name of the DSN for use by client applications</param>

        /// <param name="description">Description of the DSN that appears in the ODBC control panel applet</param>

        /// <param name="server">Network name or IP address of database server</param>

        /// <param name="driverName">Name of the driver to use</param>

        /// <param name="trustedConnection">True to use NT authentication, false to require applications to supply username/password in the connection string</param>

        /// <param name="database">Name of the datbase to connect to</param>

        public static void CreateDSN2(string dsnName, string description, string server, string driverName, bool trustedConnection, string database, string user, string password, string port)

        {

            // Lookup driver path from driver name

            var driverKey = Registry.LocalMachine.CreateSubKey(ODBCINST_INI_REG_PATH + driverName);

            if (driverKey == null) throw new Exception(string.Format("ODBC Registry key for driver '{0}' does not exist", driverName));

            string driverPath = driverKey.GetValue("Driver").ToString();

            // Add value to odbc data sources

            var datasourcesKey = Registry.LocalMachine.CreateSubKey(ODBC_INI_REG_PATH + "ODBC Data Sources");

            if (datasourcesKey == null) throw new Exception("ODBC Registry key for datasources does not exist");

            datasourcesKey.SetValue(dsnName, driverName);

            // Create new key in odbc.ini with dsn name and add values

            var dsnKey = Registry.LocalMachine.CreateSubKey(ODBC_INI_REG_PATH + dsnName);

            //MessageBox.Show(dsnKey.ToString());

            if (dsnKey == null) throw new Exception("ODBC Registry key for DSN was not created");

            dsnKey.SetValue("Data Source", dsnName);

            dsnKey.SetValue("Database", database);

            dsnKey.SetValue("Description", description);

            dsnKey.SetValue("Driver", driverPath);

            dsnKey.SetValue("Server", server);

            dsnKey.SetValue("User name", user);

            dsnKey.SetValue("Password", password);

            dsnKey.SetValue("Port", port);

            dsnKey.SetValue("Trusted_Connection", trustedConnection ? "Yes" : "No");

        }

    }

}