How to make generic provider

How to make generic provider




using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.Common;
using System.Configuration;

public partial class Default2 : System.Web.UI.Page
{



    //This Function is to Create Connection
    public static DbConnection CreateConnection(string provider, string connection)
    {
        DbConnection con = null;
        if (con == null)
        {
            try
            {
                DbProviderFactory dp = DbProviderFactories.GetFactory(provider);
                con = dp.CreateConnection();
                con.ConnectionString = connection;
            }
            catch (Exception e1)
            {
                Console.WriteLine(e1.Message);
            }
        }
        return con;
    }



    //This Function gets all DataProvider name and information
    public static DataTable GetAllProvider()
    {
        DataTable dt = DbProviderFactories.GetFactoryClasses();
        return dt;
    }

    public static string GetConnectionString(string userProviderName)
    {
        string retreive = null;

        try
        {

       

        ConnectionStringSettingsCollection c = ConfigurationManager.ConnectionStrings;
        if (c != null)
        {
            foreach (ConnectionStringSettings cs in c)
            {
                if (cs.ProviderName == userProviderName)
                {
                   retreive=  cs.ConnectionString;
                   // retreive = cs.ProviderName;
                    break;
                }
            }
        }
        return retreive;

        }
        catch (Exception)
        {
            throw;
           
           
        }
       
    }
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        DataTable dt = GetAllProvider();

        for (int i = 0; i < dt.Rows.Count; i++)
            DropDownList1.Items.Add(dt.Rows[i][2].ToString());
        GridView1.DataSource = GetAllProvider();
        GridView1.DataBind();
    }
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string _connctionstring = DropDownList1.SelectedItem.Text;
        string s = null;
        if (DropDownList1.SelectedIndex == 0)
        {
             s=GetConnectionString(_connctionstring);
             Response.Write(s);

        }
        else if (DropDownList1.SelectedIndex == 1)
        {
            s = GetConnectionString(_connctionstring);
            Response.Write(s);
        }
        else if (DropDownList1.SelectedIndex == 2)
        {
            s = GetConnectionString(_connctionstring);
            Response.Write(s);
        }
        else if (DropDownList1.SelectedIndex == 3)
        {
            s = GetConnectionString(_connctionstring);
            Response.Write(s);
        }
    }
}




change in web.config


<connectionStrings>
<clear/>  "This Tag is very important else it will not work"
<add name="Sql" connectionString="data source=72.233.78.98;uid=sa; pwd=xxxxxxxx;database=PG_SystemDB" providerName="System.Data.SqlClient"/>
<add name="Odbc" connectionString="data source=72.233.78.98;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnetdb.mdf;User Instance=true" providerName="System.Data.Odbc"/>
<add name="Oledb" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnetdb.mdf;User Instance=true" providerName="System.Data.Oledb"/>
<add name="OracleClient" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnetdb.mdf;User Instance=true" providerName="System.Data.OracleClient"/>
</connectionStrings>