Forgot Password Form Issues VB.net - vb.net

Question

I am trying to create a forgot password screen for my application. I am using the tab control for the different pages. My current code is able to create a user but it is able to create duplicates (Which is an issue needed to be rectified) I then have an issue with the forget password screen not working completely.
My code is:
Imports System.Data.OleDb
Public Class Form2
Dim connection As New OleDb.OleDbConnection
Dim dbProvider As String
Dim dbSource As String
Dim MyDocumentsFolder As String
Dim TheDatabase As String
Dim FullDatabasePath As String
Dim ds As New DataSet
Dim da As OleDb.OleDbDataAdapter
Dim sql As String
Dim DBTest1 As String
Dim DBTestP1 As String
Dim cmd As New OleDbCommand(sql, connection)
Dim connStr As String
Dim usernamevalid As Integer
Dim passwordvalid As Integer
Public Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
If User.Text.Length < 4 Then
usernamevalid = 0
ElseIf User.Text.Length > 4 Then
usernamevalid = 1
End If
If Pass.Text.Length < 5 Then
passwordvalid = 0
ElseIf Pass.Text.Length > 5 Then
passwordvalid = 1
End If
If usernamevalid = 0 Then
MsgBox("Username Must Be At Least 5 Characters")
End If
If passwordvalid = 0 Then
MsgBox("Password Must Be At Least 5 Characters")
End If
If passwordvalid And usernamevalid = 1 And Pass.Text = RePass.Text Then
dbProvider = "Provider=Microsoft.ACE.OLEDB.12.0;"
dbSource = "Data Source = C:\Users\Daniel\Documents\Robocopy.accdb"
Dim connStr = dbProvider & dbSource
DBTest1 = User.Text
DBTestP1 = Pass.Text
sql = "INSERT INTO Robocopy(username,[password],sq,sqa) VALUES('" & DBTest1 & "','" & DBTestP1 & "','" & SQREG.Text & "', '" & SQAREG.Text & "')"
Using connection = New OleDb.OleDbConnection(connStr)
Using cmd = New OleDb.OleDbCommand(sql, connection)
connection.Open()
cmd.ExecuteNonQuery()
connection.Close()
MsgBox("User Created!")
'With cmd.Parameters
'.AddWithValue("usernamer", DBTest.Text)
'.AddWithValue("password", DBTestP.Text)
'.AddWithValue("email", txtsub.text)
'.AddWithValue("contactnum", txtau.text)
'End With
'cmd.ExecuteNonQuery()
End Using
End Using
ElseIf Not Pass.Text = RePass.Text Then
MsgBox("Passwords did not match")
End If
End Sub
Private Sub Button2_Click_1(sender As Object, e As EventArgs) Handles Button2.Click
Dim result = MessageBox.Show(" Are you sure you want to quit", "Are you sure?", MessageBoxButtons.YesNoCancel)
Me.Close()
End Sub
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
If NewPass.Text = ReNewPass.Text Then
Try
connection.Open()
cmd = New OleDbCommand("update robocopy set [password] = '" & NewPass.Text & "' where username = '" & UserFGT.Text & "'", connection)
cmd.ExecuteNonQuery()
MessageBox.Show("PASSWORD CHANGE SUCCESSFULLY")
connection.Close()
Catch ex As Exception
MsgBox(ex.Message)
End Try
End If
End Sub
End Class
The exception it catches is The ConnectionString property has not been initialized
Currently I changed my code to what I think you mean:
Button4's code has been changed as such:
Private Sub ResetPassword_Click(sender As Object, e As EventArgs) Handles ResetPassword.Click
If NewPass.Text = ReNewPass.Text Then
Using connection = New OleDb.OleDbConnection(connStr)
Using cmd = New OleDb.OleDbCommand(sql, connection)
connection.Open()
cmd = New OleDbCommand("update robocopy set [password] = '" & NewPass.Text & "' where username = '" & UserFGT.Text & "'", connection)
cmd.ExecuteNonQuery()
MessageBox.Show("PASSWORD CHANGE SUCCESSFULLY")
connection.Close()
End Using
End Using
End If
End Sub
I now get the error for cmd = New OleDbCommand("update robocopy set [password] = '" & NewPass.Text & "' where username = '" & UserFGT.Text & "'", connection)
I am getting the error for cmd where it says 'Read Only' Variable cannot be the target of assignment

Answer 1

The only thing I can see wrong with the connection string are extra spaces after 'Data Source='.
Here's an example from connectionstrings.com:
Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\myFolder\myAccessFile.accdb;Persist Security Info=False;