Connection with SQL Server Part 1

In Add New Item Select Class And Language C#

Code for it:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.SqlClient;

/// <summary>
/// Summary description for Class2
/// </summary>
public class Class2
{
    SqlConnection con = new SqlConnection();
public Class2()
{

        con.ConnectionString = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|datadirectory|\\Database.mdf;Integrated Security=True;User Instance=True";
        
}
    public DataSet calldata(string str)
    {
        SqlDataAdapter adp = new SqlDataAdapter(str, con);
        DataSet ds = new DataSet();
        adp.Fill(ds);
        return ds;
    }
    public void savedata(string str)
    {
        SqlCommand cmd = new SqlCommand(str,con);
        con.Open();
        cmd.ExecuteNonQuery();
        con.Close();
    }

}