Question

Function Authenticate(ByVal UserName As String, ByVal Password As String)
    Dim con As New OleDbConnection(connectionstring)

    Dim cmdstring As String
    cmdstring = "SELECT username, password  FROM tblUsers where username = @user AND password = @pass"

    con.Open()

    Dim cmd As OleDbCommand = New OleDbCommand(cmdstring, con)

    cmd.Parameters.AddWithValue("@user", OleDbType.VarChar).Value = UserName
    cmd.Parameters.AddWithValue("@pass", OleDbType.VarChar).Value = Password

    Dim sdr As OleDbDataReader = cmd.ExecuteReader()
    If (sdr.HasRows) Then
        Authenticate = True
    Else
        Authenticate = False
    End If
    sdr.Close()
    con.Close()
    con = Nothing
    Return Authenticate
End Function

Can anybody help, not sure why I’m getting A scalar variable '@user' needs to be declared as soon as I hit this line:

Dim sdr As OleDbDataReader = cmd.ExecuteReader()

Answer 1

The answer is as follows

cmdstring = "SELECT username, password  FROM tblUsers where username = ? AND password = ?"

con.Open()

Dim cmd As OleDbCommand = New OleDbCommand(cmdstring, con)

cmd.Parameters.AddWithValue("@user", UserName)
cmd.Parameters.AddWithValue("@pass", Password)

For some reason, the ? in the queries does the trick, also the addwithvalues adds the values in the respected ? in the query, took me a while to find this, so i thought that i would share 🙂