How to data fetch login form to order form nane email contact number

Use delegate and events

After successful login, get the user's name, email and contact number from the database and pass them to the Order form using its constructor.

OrderForm frm = new OrderForm(name, email, contactNumber);
frm.Show();

In the Order form:

public OrderForm(string name, string email, string contactNumber)

{

    InitializeComponent();

    txtName.Text = name;

    txtEmail.Text = email;

    txtContact.Text = contactNumber;

}

This is a simple and clean way to pass the logged-in user's information from the Login form to the Order form.

If you're asking in Windows Forms (C#) how to pass data from one form to another, there are several common ways.

Method 1: Pass Data Through Constructor (Recommended)

Form1.cs

C#

private void btnOpenForm2_Click(object sender, EventArgs e)

{

string name = txtName.Text;

Form2 frm = new Form2(name);

frm.Show();

}

Form2.cs

C#

public partial class Form2 : Form

{

public Form2(string name)

{

InitializeComponent();

lblName.Text = name;

}

}

Method 2: Use Public Properties

Form2.cs

C#

public partial class Form2 : Form

{

public string UserName { get; set; }

private void Form2_Load(object sender, EventArgs e)

{

lblName.Text = UserName;

}

}

Form1.cs

C#

Form2 frm = new Form2();

frm.UserName = txtName.Text;

frm.Show();

Method 3: Pass Database Data (DataTable)

Form1.cs

C#

DataTable dt = GetDataFromDatabase();

Form2 frm = new Form2(dt);

frm.Show();

Form2.cs

C#

private DataTable _dt;

public Form2(DataTable dt)

{

InitializeComponent();

_dt = dt;

}

private void Form2_Load(object sender, EventArgs e)

{

dataGridView1.DataSource = _dt;

}

Example

Suppose Form1 fetches employee details from SQL Server:

C#

string empName = dr["EmployeeName"].ToString();

Form2 frm = new Form2(empName);

frm.Show();

This is a simple and clean way to pass the logged-in user's information from the Login form to the Order form .

After a successful login, read the user's details from the database, store them in an object, and pass that object to the order form. The example below is for Windows Forms. An ASP.NET Core version is at the end.

1. Create a class for the user's details

public class LoggedInUser
{
    public int Id { get; set; }
    public string Name { get; set; } = "";
    public string Email { get; set; } = "";
    public string ContactNumber { get; set; } = "";
}

2. Fetch the data in the login form

This example uses the BCrypt.Net-Next NuGet package to check the password.

private void btnLogin_Click(object sender, EventArgs e)
{
    const string sql = @"SELECT Id, Name, Email, ContactNumber, PasswordHash
                         FROM Users WHERE Email = @Email";

    using var con = new SqlConnection(connectionString);
    using var cmd = new SqlCommand(sql, con);
    cmd.Parameters.Add("@Email", SqlDbType.NVarChar, 256).Value = txtEmail.Text.Trim();

    con.Open();
    using var reader = cmd.ExecuteReader();

    if (!reader.Read() ||
        !BCrypt.Net.BCrypt.Verify(txtPassword.Text, reader["PasswordHash"].ToString()))
    {
        MessageBox.Show("Invalid email or password.");
        return;
    }

    var user = new LoggedInUser
    {
        Id = Convert.ToInt32(reader["Id"]),
        Name = reader["Name"].ToString() ?? "",
        Email = reader["Email"].ToString() ?? "",
        ContactNumber = reader["ContactNumber"].ToString() ?? ""
    };

    var orderForm = new OrderForm(user);
    orderForm.FormClosed += (s, args) => Close(); // exits the app when the hidden login form closes
    orderForm.Show();
    Hide();
}

3. Receive the data in the order form

public partial class OrderForm : Form
{
    private readonly LoggedInUser _user;

    public OrderForm(LoggedInUser user)
    {
        InitializeComponent();
        _user = user;

        txtName.Text = user.Name;
        txtEmail.Text = user.Email;
        txtContact.Text = user.ContactNumber;
    }
}

When saving the order, store _user.Id in the Orders table as the link to the user.

Important

• Always use parameters like @Email, as joining strings into SQL allows SQL injection.
• Store only a password hash, never the plain password.
• Don't pass the password to the order form.

If this is ASP.NET Core

Forms don't pass data to each other directly. Add the user's ID as a claim at login, then load their details in the order action:

[Authorize]
public async Task Order()
{
    var userId = int.Parse(User.FindFirstValue(ClaimTypes.NameIdentifier)!);
    var user = await _db.Users.FindAsync(userId);
    if (user == null) return NotFound();

    return View(new OrderViewModel
    {
        Name = user.Name,
        Email = user.Email,
        ContactNumber = user.ContactNumber
    });
}