Help Please

Question

User-527908287 posted

I am trying to set a command that will do the following things at the click of a button:

The first is to check an already existed e-mail in the database, and then if the e-mail is not in the database, it should go ahead and save the new e-mail, else it should state that the “e-mail entered already exists”.

In that same class, there should be a command to reject empty textboxes.

I will be glad if I get answers to this problem I am having in my project work.

Thank you.

My Aspx.cs code:

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

public partial class Login : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection("Data Source=(LocalDB)\\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\\Dataregister.mdf;Integrated Security=True");
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void Button2_Click(object sender, EventArgs e)
    {
        SqlCommand cmd = new SqlCommand();
        con.Open();
        cmd.CommandText = "Select * from [Table] where mail=@email";
        cmd.Parameters.AddWithValue("@email", emtxt.Text);
        cmd.Connection = con;
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr.HasRows)
        {
            Label9.Visible = true;
            Label9.Text = "e-mail alreay exists";
            Label9.ForeColor = System.Drawing.Color.Red;
        }
    
       else if (emtxt.Text != "" & signutxt.Text != "" & passtxt.Text != "")
        {
            string ins = "insert into [Table](mail, user_name, pass) values('" + emtxt.Text + "','" + signutxt.Text + "','" + passtxt.Text + "')";
            {
                SqlCommand com = new SqlCommand(ins, con);
                con.Open();
                com.ExecuteNonQuery();
                info.Text = "Sign Up Successful";
                info.ForeColor = System.Drawing.Color.Green;
                emtxt.Text = "";
                signutxt.Text = "";
                passtxt.Text = "";
                // Response.Redirect("Register.aspx");
            }
            con.Close();

        }
        else
        {
            info.ForeColor = System.Drawing.Color.Red;
            info.Text = "*All Fields Are Required*";
            emtxt.Text = "";
            signutxt.Text = "";
            passtxt.Text = "";
        }
    }

Answer 1

User-893317190 posted

Hi Donald416,

From your code , I think it has meet your require , if the email has existed, don't insert and show error message , if any of mail, user_name, pass is empty ,don't insert and show error message.

What's your problem?

If you want to simplify your code , you could try the code below.

if (emtxt.Text != "" & signutxt.Text != "" & passtxt.Text != "")
        {using (SqlConnection con = new SqlConnection(constr))
                {
                    using (SqlCommand com = new SqlCommand("if not exists ( select count(*) from [table] where mail=@mail ) begin insert into [Table](mail, user_name, pass) values(@newmail, @username,@pass) end", con))
                    {
                     // add your parameters
                           con.Open();
                       com.ExecuteNonQuery();
                   //  you could know whether  the record is inserted through the returned value of com.ExecuteNonQuery
                    // if is -1, no record is inserted
                    }
                }
           }

Best regards,

Ackerly Xu