Verifying StudentId and StudentPassword with mySql Database using Visual Basic - mysql

Question

I am working on a school voting system. I Have tried this several times and there is no error but my login button doesn't work if I enter details and click login.
I use Visual Studio 2013 and would be glad if anyone can be of assistance.
Thank you
Imports MySql.Data.MySqlClient
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
ConnectToSQL()
End Sub
'connecting to sql method
Private Sub ConnectToSQL()
Dim con As New MySqlConnection
Dim cmd As New MySqlCommand
Dim StudentId As String
Dim StudentPassword As String
Try
If con.ConnectionString = "Data source= localhost; port=3306; database= Students; user=root; password=;" Then
con.Open()
cmd.Connection = con
cmd.CommandText = "SELECT StudentId, StudentPassword, StudentName FROM members"
Dim lrd As MySqlDataReader = cmd.ExecuteReader()
If lrd.HasRows Then
While lrd.Read()
StudentId = lrd("StudentId").ToString
StudentPassword = lrd("StudentPassword").ToString
If StudentPassword = TextBox1.Text And StudentId = TextBox1.Text Then
MsgBox("you logged in succesfully")
Me.Hide()
Form2.Show()
TextBox1.Text = ""
TextBox2.Text = ""
End If
End While
Else
MsgBox("Username and password do not match")
TextBox2.Text = ""
End If
End If
Catch ex As Exception
MsgBox(ex.Message)
Finally
con.Close()
End Try
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
TextBox1.Text = ""
TextBox2.Text = ""
TextBox1.Focus()
End Sub
End Class

Answer 1

From what I can see your problem is your first if statement:
If con.ConnectionString = "Data source= localhost; port=3306; database= Students; user=root; password=;" Then
This checks if the connectionstring is set to this value and will most definitely evaluate to false.
I assume that you want to set these settings and then open the connection to the database and not check if these settings are the set to a specific string
To make it work just remove this if statement and just set the connectionstring like this and then open the connection
con.ConnectionString = "Data source= localhost; port=3306; database= Students; user=root; password=;" Then

Answer 2

First, I'm going to assume you have a typo here, as it's using the username and password as the same textbox:
If StudentPassword = TextBox1.Text And StudentId = TextBox1.Text Then
Password is probably the 2nd one, forming this:
If StudentPassword = TextBox2.Text And StudentId = TextBox1.Text Then
Since you are a student and new to this, not going to get into the parameters discussion, or SQL parameters or filtering, hashing passwords or anything like that, but a couple changes:
Your else on the not hasrows:
MsgBox("Username and password do not match")
TextBox2.Text = ""
The problem with this is that in your case, having no rows just means there's no members in the database, not really information you need, or should tell someone.
Also, you don't need to blank out the username and password if you are going to hide the form anyway. The studentFound var below is used to identify if a match was found. We want to display an error if no match was found.
So, that gives us this:
While lrd.Read()
StudentId = lrd("StudentId").ToString
StudentPassword = lrd("StudentPassword").ToString
If StudentPassword = TextBox2.Text And StudentId = TextBox1.Text Then
MsgBox("you logged in succesfully")
Me.Hide()
Form2.Show()
studentFound = True
End If
End While
If Not studentFound Then
MsgBox("Username/Password Combination Not Found")
TextBox1.Text = ""
TextBox2.Text = ""
End If