Simple way to read Login information from text file

ldpfrog · #1 July 9th, 2007, 01:30 AM

This is my first tutorial, so if there are any mistakes please forgive me =).

This will show you a very simple way to read your Login information from an outside text file.

What you need:
1. Add a new "Login Dialog" form to your project.
2. Completely erase the code inside of it, but keep the interface.
3. Create a text file listing your usernames and passwords one line after the other.

Your text file should look like this (without the numbers in front of the names):

Expand|Select|Wrap|Line Numbers

 
Username1

Password1

Username2

Password2

Username3

Password3

Etc...

Now, paste this code into your Login form.

Expand|Select|Wrap|Line Numbers

 Dim nFileNum As Integer, UInfo(999, 2) As String, sNextLine As String, lLineCount As Long, NumLine As Integer, LCount As Integer, UnPw As Integer, UnCheck As Boolean, PwCheck As Boolean, UserNum As Integer
 
Private Sub Form_Load()

UnCheck = False

PwCheck = False
 
nFileNum = FreeFile
 
Open "C:\Documents and Settings\Matt\My Documents\testing.txt" For Input As nFileNum

lLineCount = 1
 
NumLine = 0

LCount = 1

UnPw = 0
 
Do While Not EOF(nFileNum)

   Line Input #nFileNum, sText

   LCount = LCount + 1

   If LCount Mod 2 <> 0 Then UnPw = 2

   If LCount Mod 2 = 0 Then

   NumLine = NumLine + 1

   UnPw = 1

   End If

  UInfo(NumLine, UnPw) = sText

Loop
 
End Sub

Private Sub cmdCancel_Click()

    Me.Hide

    End

End Sub
 
Private Sub cmdOK_Click()

    'check for correct password

    For x = 1 To LCount

        If txtUserName = UInfo(x, 1) Then

        UnCheck = True

        UserNum = x

        End If

    Next x
 
    If txtPassword = UInfo(UserNum, 2) Then PwCheck = True
 
    If txtUserName = "" Then

      MsgBox "Invalid Username or Password, try again!", , "Login"

        txtPassword = ""

        txtPassword.SetFocus

        SendKeys "{Home}+{End}"

    ElseIf txtPassword = "" Then

       MsgBox "Invalid Username or Password, try again!", , "Login"

        txtPassword = ""

        txtPassword.SetFocus

        SendKeys "{Home}+{End}"

    ElseIf UnCheck And PwCheck = True Then

        MAINFORM.Visible = True

        Me.Enabled = False

        Me.Hide

    Else

        MsgBox "Invalid Username or Password, try again!", , "Login"

        txtPassword = ""

        txtPassword.SetFocus

        SendKeys "{Home}+{End}"

    End If
 
End Sub

Now, you are almost done.

1. Go to line 9 and change the filepath to where your text file resides.
2. Go to line 55 and change "MAINFORM" to your form that you would like to show.

Now you SHOULD be done! The way the program is written, you may have up to 999 sets of usernames and passwords.

The only problem with this is that if somebody knows where your text file is, they have all your passwords! Luckily the program I am using this for just HAPPENS to be an encryption program, so I can simply encrypt the text file. Once I have finished this I will repost on how it is done.

Killer42 · #2 July 9th, 2007, 04:05 AM

Thanks for that, ldpfrog

When I have the time one of these weekends, I may edit the article, just for consistency with various others here - one of the benefits of being a moderator. :)

I'd like to point out though, in any such case, the most basic security measure would be to store the encrypted version of each password in your file, not the "clear" version. That way, reading the file will not tell people your passwords, unless they figure out how to decrypt them. And if they wanted to edit the file to allow themselves access, they would have to encrypt their password, your way, for it to work. Certainly not impregnable, but definitely tougher than just reading the file.