User authentication for a software

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Hello,
I want to make a software that authenticates the user on its start up. I am using Windows Forms and SQL server .
I make a form called form1 with user name and password and this form runs on start up of the software. if user authentication is correct the next form called form2 runs and form1 close but when it closes the application exists totally. what I need is that form2 appears and form 1 closes without closing the application.

so any help with this plz or any ideas to make the authentication.

many thanks in advance .

Posted 14-May-11 8:08am

khaled377

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3 solutions

Solution 1

In your Program.cs file, you can make something like:

static class Program
{
  // Mark UserAuth public, AuthUserForm.cs can now change value of UserAuth.
  public static bool UserAuth = false;

  static void Main(string[] args)
  {
    // Check username and password
    Application.Run(new AuthUserForm());

    if (UserAuth)
    {
      // Username and password correct
      Application.Run(new MainForm());
    }
  }
}

And in AuthUserForm.cs, you can call Program.UserAuth = true, if username and password is correct.

Posted 14-May-11 8:20am

Kim Togo

Updated 14-May-11 19:02pm

v2

Comments

Sergey Alexandrovich Kryukov 14-May-11 14:35pm

Good answer, my 4 (I'll explain your problem below; it's minor, but will need a fix). I just wanted to post exact same solution as alternative to the one I posted, which is more standard. Your method is more clean.

Unfortunately, you did not shows how UserAuth is assigned. It won't work as is, because this static variable is private, AuthUserForm cannot access it. There can be different ways to fix it, but OP may need it.

Please see my solution, it works well but shows main form (which cannot be operated before authentication).
--SA

Kim Togo 15-May-11 1:03am

Thanks SA. And yes, I forgot to make UserAuth public.

Solution 3

Here's an article about logging in to a Winforms app:

User Login For WinForm Applications[^]

Here's a tip/trick about subsequent main forms in a winforms app:

Multiple Subsequent "Main" Forms in C# Apps[^]

Posted 14-May-11 9:39am

#realJSOP

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Sergey Alexandrovich Kryukov · Accepted Answer · 2011-05-14T08:28:00

There are different ways to do it.

Please never name anything "Form1", "Label1", etc.; renamed all created types and members to some semantic names immediately. So, you want to have two forms: AuthenticationForm and MainForm.

One way is this:

C#

partial class AuthenticationForm {
    internal bool Authenticated { get { /* returns true on success */ } }
} //class AuthenticationForm

//...

partial class MainForm {
    protected override void OnShown(EventArgs e) {
        AuthenticationForm af = new AuthenticationForm();
        af.ShowDialog();
        if (!af.Authenticated)
           Application.Exit();
    } //OnShown
    //...
} //class MainForm

//...
//just to show that MainForm is really a main one:
Application.Run(new MainForm());
//...

As the form AuthenticationForm is run in a modal form, the main form is shown but not accessible before the authentication procedure is complete, and Application.Exit guarantees that the main form will never be accessed if authentication is not successful.

This is pretty much standard way. Kim just posted an alternative answer where the main form is never shown. It requires modification of the main method (which is entry form).

The solution provided by Kim needs a fix (please see my comment to his solution). On way to fix it may be this:

C#

partial class AuthenticationForm {
    internal bool Authenticated { get { /* returns true on success */ } }
} //class AuthenticationForm

//...

static class Program {
    [System.STAThread]
    static void Main() {
        AuthenticationForm af = new AuthenticationForm();
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(af);
        if (!af.Authenticated) 
            exit;
        Application.Run(new MainForm());
    } //Main
} //class Program

—SA