I have two forms in my project (Login and Main).
What I'm trying to accoomplish is, if the login is successful, I must show the Main form and close the Login form.
I have this method in Login form that closes the Login form when the login is successful. But the Main form doesn't show.
public void ShowMain()
{
if(auth()) // a method that returns true when the user exists.
{
var main = new Main();
main.Show();
this.Close();
}
else
{
MessageBox.Show("Invalid login details.");
}
}
I tried hiding the Login form if the login process is successful. But it bothers me because I know while my program is running the login form is still there too, it should be closed right?
What should be the right approach for this? Thanks...
I think a much better method is to do this in the Program.cs file where you usually have Application.Run(form1), in this way you get a cleaner approach, Login form does not need to be coupled to Main form, you simply show the login and if it returns true you display the main form otherwise the error.
This is the most elegant solution.
private void buttonLogin_Click(object sender, EventArgs e)
{
MainForm mainForm = new MainForm();
this.Hide();
mainForm.ShowDialog();
this.Close();
}
;-)
Here's a simple solution, your problem is that your whole application closes when your login form closes right? If so, then go to your projects properties and on the Application Tab change the shutdown mode to "When last form closes" that way you can use Me.close without closing the whole program
This is my solution. Create ApplicationContext to set mainform of application and change mainform when you want to open new form and close current form.
static class Program
{
static ApplicationContext MainContext = new ApplicationContext();
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
MainContext.MainForm = new Authenticate();
Application.Run(MainContext);
}
public static void SetMainForm(Form MainForm)
{
MainContext.MainForm = MainForm;
}
public static void ShowMainForm()
{
MainContext.MainForm.Show();
}
}
When login process is complete.
private void BtLogin_Click(object sender, EventArgs e)
{
//Login Process Here.
Program.SetMainForm(new Portal());
Program.ShowMainForm();
this.Close();
}
I hope this will help you.
Try this:
public void ShowMain()
{
if(auth()) // a method that returns true when the user exists.
{
this.Close();
System.Threading.Thread t = new System.Threading.Thread(new System.Threading.ThreadStart(Main));
t.Start();
}
else
{
MessageBox.Show("Invalid login details.");
}
}
[STAThread]
public void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Main());
}
You must call the new form in a diferent thread apartment, if I not wrong, because of the call system of windows' API and COM interfaces.
One advice: this system is high insecure, because you can change the if condition (in MSIL) and it's "a children game" to pass out your security. You need a stronger system to secure your software like obfuscate or remote login or something like this.
Hope this helps.
I would do this the other way round.
In the OnLoad event for your Main form show the Logon form as a dialog. If the dialog result of that is OK then allow Main to continue loading, if the result is authentication failure then abort the load and show the message box.
EDIT Code sample(s)
private void MainForm_Load(object sender, EventArgs e)
{
this.Hide();
LogonForm logon = new LogonForm();
if (logon.ShowDialog() != DialogResult.OK)
{
//Handle authentication failures as necessary, for example:
Application.Exit();
}
else
{
this.Show();
}
}
Another solution would be to show the LogonForm from the Main method in program.cs, something like this:
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
LogonForm logon = new LogonForm();
Application.Run(logon);
if (logon.LogonSuccessful)
{
Application.Run(new MainForm());
}
}
In this example your LogonForm would have to expose out a LogonSuccessful bool property that is set to true when the user has entered valid credentials
best way for show login for and close login form before login successfully put login form in FrmMain after InitializeComponent.
public FrmMain()
{
FrmSplash FrmSplash = new FrmSplash();
FrmSplash.ShowDialog();
InitializeComponent();
//Login Section
{
public void ShowMain()
{
if(auth()) // a method that returns true when the user exists.
{
this.Hide();
var main = new Main();
main.Show();
}
else
{
MessageBox.Show("Invalid login details.");
}
}
It's simple.
Here is the code.
private void button1_Click(object sender, EventArgs e)
{
//creating instance of main form
MainForm mainForm = new MainForm();
// creating event handler to catch the main form closed event
// this will fire when mainForm closed
mainForm.FormClosed += new FormClosedEventHandler(mainForm_FormClosed);
//showing the main form
mainForm.Show();
//hiding the current form
this.Hide();
}
// this is the method block executes when main form is closed
void mainForm_FormClosed(object sender, FormClosedEventArgs e)
{
// here you can do anything
// we will close the application
Application.Exit();
}
static class Program
{
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Login();
}
private static bool logOut;
private static void Login()
{
LoginForm login = new LoginForm();
MainForm main = new MainForm();
main.FormClosed += new FormClosedEventHandler(main_FormClosed);
if (login.ShowDialog(main) == DialogResult.OK)
{
Application.Run(main);
if (logOut)
Login();
}
else
Application.Exit();
}
static void main_FormClosed(object sender, FormClosedEventArgs e)
{
logOut= (sender as MainForm).logOut;
}
}
public partial class MainForm : Form
{
private void btnLogout_ItemClick(object sender, ItemClickEventArgs e)
{
//timer1.Stop();
this.logOut= true;
this.Close();
}
}
Evan the post is too old i like to give you a trick to do this if you wants to show splash/login screen and when the progress bar of splash screen get certain value/or successful login happen and closed the splash/login then re show the main form, frm-main will be the startup form not frm-spalash
in frm-main
public partial class frmMain : Form
{
public frmMain()
{
frmSplash frm = new frmSplash();
frm.Show(); // new splash screen will shows
this.Opacity=0; // will hide your main form
InitializeComponent();
}
}
in the frm-Splash
private void timer1_Tick(object sender, EventArgs e)
{
int cnt = progressBar1.Value;
switch (cnt)
{
case 0:
//Do sum stuff
break;
case 100:
this.Close(); //close the frm-splash
frmMain.ActiveForm.Opacity = 100; // show the frm-main
break;
}
progressBar1.Value = progressBar1.Value+1;
}
if you use it for login form
private void btlogin_Click(object sender, EventArgs e)
{
bool login = false;
//try your login here
//connect your database or whatever
//and then when it success update login variable as true
if(login == true){
this.Close(); //close the frm-login
frmMain.ActiveForm.Opacity = 100; // show the frm-main
}else{
//inform user about failed login
}
}
note that i use a timer and a progress bar to manipulate the actions you don't need those two it just for sake of complete answer only, hope this helps
you should do it the other way round:
Load the mainform
first and in its onload
event show your loginform
with showdialog()
which will prevent mainform
from showing until you have a result from the loginform
EDIT:
As this is a login form and if you do not need any variables from your mainform
(which is bad design in practice), you should really implement it in your program.cs as Davide and Cody suggested.
try this
private void cmdLogin_Click(object sender, EventArgs e)
{
if (txtUserName.Text == "admin" || txtPassword.Text == "1")
{
FrmMDI mdi = new FrmMDI();
mdi.Show();
this.Hide();
}
else {
MessageBox.Show("Incorrect Credentials", "Library Management System", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
}
and when you exit the Application you can use
Application.Exit();
Source: Stackoverflow.com