Default login form not functioning

[Sport Girl]

Hi Everybody,

Please can somebody help me with this little task:

i created a login form in windows form from the default template in VB.NET but the problem is that it is not functioning even with the correct corresponding code without any errors.
Well it is always prompting the messagebox "you must enter a username" whenever the situation is, besides the canccel button does not work in closing the form

Imports System.Windows.Forms
 
Imports System.Data.SqlClient
Imports System.Security
Imports System.Security.Cryptography
 
Public Class LoginForm
    Inherits System.Windows.Forms.Form
 
    ' TODO: Insert code to perform custom authentication using the provided username and password 
    ' (See [url]http://go.microsoft.com/fwlink/?LinkId=35339[/url]).  
    ' The custom principal can then be attached to the current thread's principal as follows: 
    '     My.User.CurrentPrincipal = CustomPrincipal
    ' where CustomPrincipal is the IPrincipal implementation used to perform authentication. 
    ' Subsequently, My.User will return identity information encapsulated in the CustomPrincipal object
    ' such as the username, display name, etc.
 
    Private Sub LoginForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 
        InitializeComponent()
 
 
    End Sub
    Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
 
        Dim AuthenticationReader As System.Data.SqlClient.SqlDataReader
 
        'Intitalizes connection object
        Dim SqlConnection As New SqlClient.SqlConnection
        SqlConnection.ConnectionString = "Server=owner;database=***"
 
        'Initializes command object to execute statements.
        Dim AuthenticationCommand As New SqlClient.SqlCommand
        AuthenticationCommand.Connection = SqlConnection
 
        'Declarations
        Dim DBusername As String
        Dim DBuserpassword
        Dim DBuserID As Integer
        Dim DBlogggedname As String
        Dim DBprivilege As String
        
        If UsernameTextBox.Text.Length = 0 Then
 
 
            MessageBox.Show("You must enter a username", "Invalid Username", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            UsernameTextBox.Focus()
 
 
 
        ElseIf PasswordTextBox.Text.Length = 0 Then
 
            MessageBox.Show("You must enter a password", "Invalid Password", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            PasswordTextBox.Focus()
        Else
 
            DBusername = Me.UsernameTextBox.Text
            DBuserpassword = Me.PasswordTextBox.Text
 
 
            'Executes command
            Dim AuthenticationString As String
            AuthenticationString = "select *  from *** where UserName=  '" & UsernameTextBox.Text & "'"
 
            AuthenticationCommand.CommandText = AuthenticationString
            SqlConnection.Open()
            AuthenticationCommand.ExecuteNonQuery()
 
            'Encrypt Password
            Dim md5hasher As New MD5CryptoServiceProvider
            Dim hashedBytes As Byte()
            Dim encoder As New System.Text.UTF8Encoding
 
            hashedBytes = md5hasher.ComputeHash(encoder.GetBytes(PasswordTex  tBox.Text))
 
 
           
 
            AuthenticationReader = AuthenticationCommand.ExecuteReader()
            If AuthenticationReader.HasRows Then
                While (AuthenticationReader.Read())
                    DBusername = AuthenticationReader("UserName")
                    DBuserpassword = AuthenticationReader("Password")
                    DBuserID = AuthenticationReader("UserID")
                    DBlogggedname = AuthenticationReader("Name")
                    DBprivilege = Trim(AuthenticationReader("Privilege"))
                End While
            Else
 
                MessageBox.Show("Invalid username!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
                UsernameTextBox.Focus()
                Exit Sub
            End If
            AuthenticationReader.Close()
 
            SqlConnection.Close()
 
 
 
            If bHashEquals(hashedBytes, DBuserpassword) Then
 
 
                Dim Frame As New Frame()
                Frame.Show()
                Me.Hide()
 
            Else
 
                MessageBox.Show("Invalid password!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
                PasswordTextBox.Focus()
            End If
        End If
 
 
 
 
    End Sub
    Private Function bHashEquals(ByVal byHash1 As Byte(), ByVal byHash2() As Byte) As Boolean
        bHashEquals = False
        If byHash1.Length = byHash2.Length Then
            Dim i As Integer
            Do While (i < byHash1.Length) AndAlso (byHash1(i) = byHash2(i))
                i = i + 1
            Loop
            If i = byHash1.Length Then
                bHashEquals = True
            End If
        End If
 
    End Function
 
    Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Cancel.Click
        Me.Close()
    End Sub
 
End Class

Regards