my system cant close after get pass the log-in form

[micheal]

Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
Dim con As New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database1.mdf;Integrated Security=True;User Instance=True")
Dim cmd As SqlCommand = New SqlCommand("SELECT * FROM Staff WHERE username = '" & UsernameTextBox.Text & "' AND password = " & PasswordTextBox.Text, con)
con.Open()
Dim sdr As SqlDataReader = cmd.ExecuteReader()
If (sdr.Read() = True) Then
MessageBox.Show("The user is valid!")
Me.Hide()
Form17.ShowDialog()
con.Close()
Else
MessageBox.Show("Invalid username or password!")
End If
End Sub

comment
'where i do wrong,please help,your kind help much more appreciated.

 

[JohnH]

You are hiding your startup form (and never close it), while you have application shutdown mode to close when startup form closes.
May I suggest you do login dialog from applications startup event handler, and set your main form as startup form?

Also update your forum profile, you can't be using .Net 1.0.

 

[micheal]

the reason why i hiding the start up(and never close it) because if i put me.close on the log-in form,the from will automatically close after click submit username and password,without enter the main form application,how to do as your suggestion?

my application should be run like this :- log-in form(start up) ->main form application
'thank you for your advise.

 

[JohnH]

Start with these:
Startup Event
ShowDialog Method