usersignup.aspx.cs

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

namespace RegisterLogin
{
    public partial class usersignup : System.Web.UI.Page
    {
        string strcon = ConfigurationManager.ConnectionStrings["con"].ConnectionString;
        protected void Page_Load(object sender, EventArgs e)
        {

        }
        //sign up button click event
        protected void Button1_Click(object sender, EventArgs e)
        {
            if(checkUserExists())
            {
                Response.Write("<script>alert('User already exists! Try another email');</script>");
            }
            else
            {
                signUpNewUser();
            }
        }

        bool checkUserExists()
        {
            try
            {
                SqlConnection con = new SqlConnection(strcon);
                if (con.State == ConnectionState.Closed)
                {
                    con.Open();
                }
                SqlCommand cmd = new SqlCommand("select * from user_info where email='"+TextBox3.Text.Trim()+"';", con);
                SqlDataAdapter da=new SqlDataAdapter(cmd);
                DataTable dt = new DataTable();
                da.Fill(dt);
                if(dt.Rows.Count>0)
                {
                    return true;
                }
                else
                {
                    return false;
                }
               
            }
            catch (Exception ex)
            {
                Response.Write("<script>alert(' " + ex.Message + "');</script>");
                return false;
            }
            
        }

        void signUpNewUser()
        {
            try
            {
                SqlConnection con = new SqlConnection(strcon);
                if (con.State == ConnectionState.Closed)
                {
                    con.Open();
                }
                SqlCommand cmd = new SqlCommand("insert into user_info(fullname,dateofbirth,email,contact,password) values (@fullname,@dateofbirth,@email,@contact,@password)", con);
                cmd.Parameters.AddWithValue("@fullname", TextBox1.Text.Trim());
                cmd.Parameters.AddWithValue("@dateofbirth", TextBox2.Text.Trim());
                cmd.Parameters.AddWithValue("@email", TextBox3.Text.Trim());
                cmd.Parameters.AddWithValue("@contact", TextBox4.Text.Trim());
                cmd.Parameters.AddWithValue("@password", TextBox5.Text.Trim());


                cmd.ExecuteNonQuery();
                con.Close();
                Response.Write("<script>alert('Sign Up Succesful. Go to user login page');</script>");
            }
            catch (Exception ex)
            {
                Response.Write("<script>alert(' " + ex.Message + "');</script>");
            }
        }
    }
}