Troubles with code for login on Access - ms-access

Question

I am new to VB Scripting and Scripting of any kind but I am a fast learner.
I have with the help of various aids been developing an Access database where scripting is used.
I have developed the below script as part of a login screen.
Private Sub cmdLogin_Click()
Dim dbs As Database
Dim rstUserPwd As Recordset
Dim bFoundMatch As Boolean
Set dbs = CurrentDb
Set rstUserPwd = dbs.OpenRecordset("qryUserPwd")
bFoundMatch = False
If rstUserPwd.RecordCount > 0 Then
rstUserPwd.MoveFirst
' check for matching records
Do While rstUserPwd.EOF = True
If rstUserPwd![UserName] = frmLogin.txtUsername.Value And rstUserPwd![Password] = frmLogin.txtPassword.Value Then
bFoundMatch = True
Exit Do
End If
rstUserPwd.MoveNext
Loop
End If
If bFoundMatch = True Then
'Open the next form here and close this one
DoCmd.Close acForm, Me.Name
DoCmd.OpenForm "frmNavigation"
Else
'
MsgBox "Incorrect Username or Password"
End If
rstUserPwd.Close
End Sub
Even though I enter the correct username and password I get the "Incorrect Username or Password message pop up. Can anyone help by telling me what I have done wrong please. If needed I can add a copy of the database.

Answer 1

Carefully consider the logic in this line ...
Do While rstUserPwd.EOF = True
That says to VBA, "run the code in this block while the condition is True". However, when you first encounter that line, your recordset's current row is the first row (as a result of MoveFirst). And therefore EOF is False, and since False is not equal to True, the code in the Do While loop is not run.
My first guess is you want something like this to control the loop.
Do While Not rstUserPwd.EOF
That change might get your code working as you intend. However that approach is more complicated than necessary. Instead of opening a recordset and walking the rows to check for a user name and password match, you could use a DCount expression.

Answer 2

I asume the username and password are both string values and would suggest changing your code as following:
Dim sSql As String
Dim rstUserPwd As DAO.Recordset
Dim bFoundMatch As Boolean
sSql = "Select * from qryUserPwd Where UserName='" & Nz(frmLogin.txtUsername, "") & "' And Password = '" & Nz(frmLogin.txtPassword, "") & "'"
Set rstUserPwd = CurrentDb.OpenRecordset(sSql, dbOpenSnapshot)
If Not (rstUserPwd.BOF And rstUserPwd.EOF) Then
bFoundMatch = True
End If
rstUserPwd.Close: Set rstUserPwd = Nothing
If bFoundMatch = True Then
'Open the next form here and close this one
DoCmd.Close acForm, Me.Name
DoCmd.OpenForm "frmNavigation"
Else
'
MsgBox "Incorrect Username or Password"
End If

Answer 3

You could also use this 1 liner:
bFoundMatch = DCount("*", "qryUserPwd", "UserName = '" & frmLogin.txtUsername & "' And Password = '" & frmLogin.txtPassword & "'") > 0