Null connection - Connecting to ASP.NET - Microsoft SQL Server

Question

I have been trying to connect to database, but it shows 'null' error. So, I tried opening the previous form that I practiced on, it turned out to be perfectly fine.

This is my code:

string username = txtusername.Text;
        string firstname = txtfirstname.Text;
        string lastname = txtlastname.Text;
        string email = txtemail.Text;
        string password = txtpass.Text;
        string gender = rbgender.Text;
        string nationality = dcountry.Text;
        string phone = txtphone.Text;

        string connection = ConfigurationManager.ConnectionStrings["connectionString"].ConnectionString;
        SqlConnection connect = new SqlConnection(connection);
        string command = "INSERT INTO Persons(username, firstname, lastname, email, password, gender, nationality, phone) VALUES('@username','@firstname','@lastname','@email','@password','@gender','@nationality','@phone')";


        SqlCommand insert = new SqlCommand(command +","+ connection);
        insert.Parameters.AddWithValue("@username", username);
        insert.Parameters.AddWithValue("@firstname", firstname);
        insert.Parameters.AddWithValue("@lastname", lastname);
        insert.Parameters.AddWithValue("@email", email);
        insert.Parameters.AddWithValue("@password", password);
        insert.Parameters.AddWithValue("@gender", gender);
        insert.Parameters.AddWithValue("@nationality", nationality);
        insert.Parameters.AddWithValue("@phone", phone);
        insert.ExecuteNonQuery();
        connect.Close();

Does it have anything to do with the connectionstrings in web.config?

 <connectionStrings>
<add name="ApplicationServices"
     connectionString="Data Source=ADRIAN-LAPTOP\SQL;Initial Catalog=New;Integrated Security=True"
     providerName="System.Data.SqlClient" />

Can you add a try catch, and take exception, because is more easy know whats is exactly happening. — danywalls
– danywalls, Commented Jun 28, 2013 at 9:23
In addition to what others have already said, SqlCommand insert = new SqlCommand(command +","+ connection); should be SqlCommand insert = new SqlCommand(command, connection);. Or even better, wrap it in using(...) { ... }. — user1429080
– user1429080, Commented Jun 28, 2013 at 10:09

KV Prajapati · Accepted Answer · 2013-06-28 09:27:35Z

8

Key in web.config file is different then it is used in code.

It should be,

string connection = ConfigurationManager.ConnectionStrings["ApplicationServices"]
                                        .ConnectionString;

And no need to wrap parameter names in single quote.

 string command = @"
   INSERT INTO Persons
      (username, firstname, lastname, email, password, gender, nationality,phone) 
     VALUES
      (@username,@firstname,@lastname,@email,@password,@gender,@nationality,@phone)";

A side note, always dispose the ADO resources by using the using statement ( or calling Dispose()).

using(SqlConnection connect = new SqlConnection(connectionString))
 {
  //
 }

edited Jun 28, 2013 at 9:27

answered Jun 28, 2013 at 9:22

KV Prajapati

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1 Comment

Belzelga Over a year ago

Wow, thank you. I also noticed( I actually received an error ) that I forgot to open the connection. XD

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