Vb.net - Create a login form using a datareader

[dday9]

Prerequisits:

1. 2 Labels
2. 2 Textbox's
3. 2 Buttons
4. MS Access or SQL database

The 2 TextBox's are named:

1. txt_Username
2. txt_Password

The 2 Button's are named:

1. btn_OK
2. btn_Cancel

The Database's datatable should be named "login" and have 2 datafields. Both fields should be string's. They are named:

• username
• password

Oledb:

Option Strict On
Option Explicit On

Imports System.Data.OleDb
Public Class Form1
    Private Sub btn_OK_Click(sender As System.Object, e As System.EventArgs) Handles btn_OK.Click
        'Declare the oledbconnection adn oledbcommand
        Dim con As New OleDbConnection("MyConnectionString")
        Dim cmd As New OleDbCommand("SELECT username,password FROM login WHERE username = ? AND password = ?", con)

        'Set up parameters for the oledbcommand
        cmd.Parameters.AddWithValue("username", txt_Username.Text)
        cmd.Parameters.AddWithValue("password", txt_Password.Text)

        'If the username or password is empty then throw an error
        If txt_Username.Text = String.Empty Then
            MessageBox.Show("Please enter the username.", Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
        ElseIf txt_Password.Text = String.Empty Then
            MessageBox.Show("Please enter the password.", Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
        Else
            Try
                'Open the connection and declare an oledbreader
                con.Open()
                Dim reader As OleDbDataReader = cmd.ExecuteReader

                'If our reader has one or more rows then read those rows and compare the text
                If reader.HasRows = True Then
                    reader.Read()
                    'If the username and password match then it's a success
                    If txt_Username.Text = reader.Item("username").ToString And txt_Password.Text = reader.Item("password").ToString Then
                        MessageBox.Show("Login successful")
                    Else
                        'If they don't match than throw an error
                        MessageBox.Show("Login Failed." & Environment.NewLine & _
                                        "Username and password are casesensitive.", _
                                        Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
                    End If
                End If
            Catch ex As Exception
                MessageBox.Show(ex.ToString, Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
            Finally
                con.Close()
            End Try
        End If
    End Sub

    Private Sub btn_Cancel_Click(sender As System.Object, e As System.EventArgs) Handles btn_Cancel.Click
        Me.Close()
    End Sub
End Class

SQL:

Option Strict On
Option Explicit On

Imports System.Data.SqlClient
Public Class Form1
    Private Sub btn_OK_Click(sender As System.Object, e As System.EventArgs) Handles btn_OK.Click
        'Declare the sqlconnection adn sqlcommand
        Dim con As New SqlConnection("MyConnectionString")
        Dim cmd As New SqlCommand("SELECT username,password FROM login WHERE username = ? AND password = ?", con)

        'Set up parameters for the sqlcommand
        cmd.Parameters.AddWithValue("@username", txt_Username.Text)
        cmd.Parameters.AddWithValue("@password", txt_Password.Text)

        'If the username or password is empty then throw an error
        If txt_Username.Text = String.Empty Then
            MessageBox.Show("Please enter the username.", Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
        ElseIf txt_Password.Text = String.Empty Then
            MessageBox.Show("Please enter the password.", Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
        Else
            Try
                'Open the connection and declare an sqlreader
                con.Open()
                Dim reader As SqlDataReader = cmd.ExecuteReader

                'If our reader has one or more rows then read those rows and compare the text
                If reader.HasRows = True Then
                    reader.Read()
                    'If the username and password match then it's a success
                    If txt_Username.Text = reader.Item("username").ToString And txt_Password.Text = reader.Item("password").ToString Then
                        MessageBox.Show("Login successful")
                    Else
                        'If they don't match than throw an error
                        MessageBox.Show("Login Failed." & Environment.NewLine & _
                                        "Username and password are casesensitive.", _
                                        Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
                    End If
                End If
            Catch ex As Exception
                MessageBox.Show(ex.ToString, Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
            Finally
                con.Close()
            End Try
        End If
    End Sub

    Private Sub btn_Cancel_Click(sender As System.Object, e As System.EventArgs) Handles btn_Cancel.Click
        Me.Close()
    End Sub
End Class