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How to close the former form?

Hi. I have built a login form which links to a main form. After check user's ID and password, i use such codes:

Dim newForm as New mainForm
mainForm.show()

Here i do not know how to close the form login form, me.close() and me.disposal() do not work well. anyone can help me? thanks!

[296 byte] By [phil_lee] at [2008-2-15]

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# 1

Try Form.Hide(). This may not be the most elegant of solutions.

By the way, why is close() not working?

JagadiskKulkarni at 2007-9-9 >

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# 2

since me.close() will close both login and main form , i do not know the reason

phil_lee at 2007-9-9 >

# 3

You should not have your Login form as the first form, you should have the MainForm as the first form, then from MainForm you can add code to create this Login form from the InitializeComponent and from the login form you can then have a event handler to close the login form after user successfully login.

Sample code

In the MainForm

Private Sub InitializeComponent()
components = New System.ComponentModel.Container()
mainMenu1 = New System.Windows.Forms.MainMenu()

Me.Menu = mainMenu1
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Dpi
Me.Text = "Form1"
Me.AutoScroll = True

Dim loginForm As New LoginForm()
loginForm.ShowDialog()

End Sub

In the LoginForm add the following event handler
Private Sub Login_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Login.Click
'Do login verification
Me.Close()
End Sub
David

DavidTSoMSFT at 2007-9-9 >

# 4

Hello David,
I've translated your VB code to C# for my needs. The login functionality works correctly.

Well, I wanted to give the user an option to close the login form and exit the application, so I added a new, second button named "Cancel", next to my "Login" button. The button2_Click method is placed at the login form file, whitch is Form1.cs for me. At the MainForm.cs I've tryed any combination of:

components.Dispose();
Me.Dispose();

public MainForm()
{
InitializeComponent();

components = new System.ComponentModel.Container();
MainMenu Me = new System.Windows.Forms.MainMenu();

Form1 loginForm = new Form1();
loginForm.ShowDialog();

if (Thread.CurrentPrincipal.Identity.IsAuthenticated != true)
{
components.Dispose();
Me.Dispose();
}
}

What I got as a result was: login form is closed and the MainForm is started.

How to make the login form (and the entire application) to be closed, and not the MainForm to be started?

burov at 2007-9-9 >

# 5

Instead of trying to dispose of the form in the constructor (bad idea), set a flag and call MainForm.Close in the Load event

AlexFeinman at 2007-9-9 >

# 6

Thank you Alex!

Here is my solution of the problem:

private void MainForm_Load(object sender, EventArgs e)
{
if (Thread.CurrentPrincipal.Identity.IsAuthenticated == false)
{
this.Dispose();
}
}

burov at 2007-9-9 >

# 7

Hi David,

just a short query with regard of your suggested code to display login form from MDI Parent form and not vice verse.

Did i understood you correctly that to build modal Login form, one should add in MDIParent.Designer.vb the following lines of code:

Dim loginForm As New fclsLogin()

loginForm.ShowDialog()

I tried this code and it works well in the run time. The login form shows first and after authentication on ok_click event it closes and opens MDI Parent and child forms. Saying this i have also to point that every time after debugging when i press on view MDIParent Design, it returns en error-warning:

Warning 1 Form that is already visible cannot be displayed as a modal dialog box. Set the form's visible property to false before calling showDialog. C:\ModellingFM\Examples\Ch17\APITotal\ParentForm\MDIParent1.Designer.vb 365 0

I was trying to find in properties section of both login form and main form the visible property but it can't be find. Can you please tell me if this warning can affect the application deployment.

danhood at 2007-9-9 >

# 8

Hi David,

I tried your suggestion to close the login form. But when Login form is closed, the MainForm shows up. Could you give me some help? Thank you so much.

-Joey

喬伊 at 2007-9-9 >

# 9

Hello Joey,

Do you really close your loginform or just hide it? And on which form is the MessageLoop running (search for Application.Run)?

Greetings from the rainy Netherlands.

PeterVrenken at 2007-9-9 >

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