Here’s the code to insert a record into your table using ASP.NET and C# in your aspx.cs file. This assumes you have input fields in your .aspx page with IDs txtUsername, txtEmail, txtPhone, txtArea, txtCity, txtCountry, txtPostalCode, and txtFullName.

Code in YourPage.aspx.cs

using System;
using System.Data.SqlClient;
using System.Configuration;

public partial class YourPage : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        // Code for any Page_Load events
    }

    protected void btnSave_Click(object sender, EventArgs e)
    {
        // Fetch the connection string from Web.config
        string connectionString = ConfigurationManager.ConnectionStrings["doctopsdbConnectionString"].ConnectionString;

        // Insert SQL query
        string query = "INSERT INTO user_master (username, email, phone, area, city, country, postalcode, fullname) " +
                       "VALUES (@Username, @Email, @Phone, @Area, @City, @Country, @PostalCode, @FullName)";

        // Using block to ensure proper disposal of resources
        using (SqlConnection conn = new SqlConnection(connectionString))
        {
            using (SqlCommand cmd = new SqlCommand(query, conn))
            {
                // Define parameters and assign values from text boxes
                cmd.Parameters.AddWithValue("@Username", txtUsername.Text);
                cmd.Parameters.AddWithValue("@Email", txtEmail.Text);
                cmd.Parameters.AddWithValue("@Phone", txtPhone.Text);
                cmd.Parameters.AddWithValue("@Area", txtArea.Text);
                cmd.Parameters.AddWithValue("@City", txtCity.Text);
                cmd.Parameters.AddWithValue("@Country", txtCountry.Text);
                cmd.Parameters.AddWithValue("@PostalCode", txtPostalCode.Text);
                cmd.Parameters.AddWithValue("@FullName", txtFullName.Text);

                try
                {
                    // Open the connection
                    conn.Open();
                    // Execute the command
                    int rowsAffected = cmd.ExecuteNonQuery();

                    if (rowsAffected > 0)
                    {
                        // Record was successfully inserted
                        lblMessage.Text = "Record inserted successfully!";
                    }
                    else
                    {
                        lblMessage.Text = "No record inserted.";
                    }
                }
                catch (Exception ex)
                {
                    // Display error message
                    lblMessage.Text = "Error: " + ex.Message;
                }
            }
        }
    }
}

Explanation:

1. Connection String: Retrieves the connection string from Web.config.
2. SQL Command: Uses a parameterized SQL query to prevent SQL injection.
3. Parameters: Parameters like @Username, @Email, etc., match the column names in the database.
4. Exception Handling: Catches any exceptions and displays the error message in lblMessage.

Notes:

• Ensure that the button triggering the btnSave_Click event is defined in your .aspx file.
• lblMessage is a Label control used to display success or error messages. Make sure to add it to the .aspx page.