how to show login form on front & Mainform Behind Login Form?

Question

In my winform application; I have login form and main form.

When I run program I want the login form on top and main form behind it.

One more thing is until I do not login properly with username and password, the main form should not be accessible and only the login form should accessible.

My Language is C#.Net.

Please provide idea on how to achieve this?

Instead of simply having the main form behind your login form, you could have it hidden until the username/password are correct. — Ari, Jul 30 '12 at 06:33
Do you want that your Login form shown first and if login is successfull your main form will be shown? — Adil Mammadov, Jul 30 '12 at 06:57

Ria · Accepted Answer · 2012-07-30T07:39:15.323

2

Use Form.ShowDialog (Shows the form as a modal dialog box) on the your Form.OnShown event (Occurs whenever the form is first displayed):

private void Form1_Load(object sender, EventArgs e)
{
    this.Shown += Form1_Shown;
}

private void Form1_Shown(object sender, EventArgs e)
{
    LoginForm loginForm  = new LoginForm ();

    if (loginForm.ShowDialog() == DialogResult.Ok)
    {
     ....
    }
}

your Program and LoginForm like this:

//Progrmm.cs
Application.Run(new Form1());

//LoginForm.cs
public partial class LoginForm : Form
{
    public LoginForm ()
    {
        InitializeComponent();
    }

    private void buttonLogin_Click(object sender, EventArgs e)
    {
        //check username password
        if(texboxUser == "user" && texboxPassword == "password")
        {
            DialogResult = DialogResult.OK;
            Close();
        }
        else
        {
            MessageBox.Show("Wrong user pass");
        }
    }
}

edited Jul 30 '12 at 07:39

answered Jul 30 '12 at 06:48

Ria

10,237
3
33
60

this code is for main form and what code should be login form? – Pinakin Miyani Jul 30 '12 at 06:54
what should i write in program.cs file – Pinakin Miyani Jul 30 '12 at 07:09
@PinakinMiyani: no need to change `program.cs`. i updated my answer – Ria Jul 30 '12 at 07:15
but when i run my program main form is directly opens.login form is not opening – Pinakin Miyani Jul 30 '12 at 07:21
@PinakinMiyani: sorry. use `Form.OnShown`. i updated my answer. – Ria Jul 30 '12 at 07:29
i tried this but still i'm getting main form. login form is not coming. I had debug n show that it is not entering in main forms load event – Pinakin Miyani Jul 30 '12 at 07:32
i updated my answer: add to form's `Shown` event like my code. see `Form1_Shown`. i checked and works correctly – Ria Jul 30 '12 at 07:34
Form that is already visible cannot be displayed as a modal dialog box. Set the form's visible property to false before calling showDialog.this error is coming when i running code – Pinakin Miyani Jul 30 '12 at 07:39
Form that is already visible cannot be displayed as a modal dialog box. Set the form's visible property to false before calling showDialog.this error is coming when i running code – Pinakin Miyani Jul 30 '12 at 07:41
i want solution for report can you help me @ria – Pinakin Miyani Jul 30 '12 at 07:56

nawfal · Answer 2 · 2012-07-30T06:53:07.553

0

I for one do not like the design you proposed, would want to first show the Login form, then the mainform. But if you absolutely need it, then you can do the below..

In Main class:

Application.Run(new frmMain());

And then in Form class:

private void frmMain_Load(object sender, EventArgs e)
{
    //---------------------------------------------


    System.Windows.Forms.Timer t = new System.Windows.Forms.Timer();
    t.Tick +=new EventHandler(t_Tick);
    t.Interval = 1000;
    t.Start();
}

void t_Tick(object sender, EventArgs e)
{
    frmLogin l = new frmLogin();
    if (l.ShowDialog(this) == DialogResult.Ok)
       ((System.Windows.Forms.Timer)sender.Dispose();
}

Though you have to further ensure that the login form is not exited without proper username and password (that should be upto you)

Use System.Windows.Forms.Timer because it runs in the same thread and hence would block the calls to main form (unlike System.Timers.Timer)

edited Jul 30 '12 at 06:53

answered Jul 30 '12 at 06:39

nawfal

70,104
56
326
368

System.Timers.Timer t = new System.Timers.Timer(1000); t.Elapsed += new System.Timers.ElapsedEventHandler(t_Elapsed); t.Start(); } void t_Elapsed(object sender, System.Timers.ElapsedEventArgs e) { frmLogin l = new frmLogin(); if (l.ShowDialog() == DialogResult.Ok) ((System.Timers.Timer)sender.Dispose(); }where i put this code in login form or in main form – Pinakin Miyani Jul 30 '12 at 06:41
if (l.ShowDialog() == DialogResult.Ok) ((System.Timers.Timer)sender.Dispose(); this part is giveing me error. what should be code for login form? – Pinakin Miyani Jul 30 '12 at 06:49

how to show login form on front & Mainform Behind Login Form?

2 Answers2

Linked