Artikel ini lanjutan dari part 1 . Dan ini dia source code langkap nya: Imports System.Data Imports MySql.Data.MySqlClient Public Class LoginForm1 Dim iFail As Integer Private Sub LoginForm1_Load( ByVal sender As Object, _ ByVal e As System.EventArgs) Handles Me .Load iFail = 0 End Sub Function CheckLogin( ByVal UserName As String , _ ByVal Password As String ) As Integer Dim conn As MySqlConnection Dim cmd As New MySqlCommand Dim objValue As Object conn = New MySqlConnection() conn.ConnectionString = "server=localhost;user id=root;" & _ "password=;database=latihan" Try conn.Open() cmd.Connection = conn cmd.CommandText = "SELECT COUNT(username) AS getin " & _ "FROM tbluser WHERE username = " & _ "'" & UserName & "' AND " & _ "password = '" & Password & "'" objValue = cmd.ExecuteScalar() conn.Close() If objValue Is Nothing Then Return 0 Else Return objValue.ToString End If Catch myerror As MySqlException MessageBox.Show( "Error: " & myerror.Message) Finally conn.Dispose() End Try Return 0 End Function Private Sub OK_Click( ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles OK.Click Dim strUserName As String = UsernameTextBox.Text Dim strPassword As String = PasswordTextBox.Text If strUserName = String .Empty Then _ MsgBox( "Username belum diisi!" ) : Exit Sub If strPassword = String .Empty Then _ MsgBox( "Password belum diisi!" ) : Exit Sub Try If CheckLogin(strUserName, strPassword) > 0 Then MsgBox( "Welcome " & strUserName & "!" ) 'tulis code lainnya setelah login disini Me .Close() Else iFail = iFail + 1 If iFail >= 3 Then MsgBox( "Gagal login 3 kali." & vbCrLf & _ "Aplikasi akan ditutup." ) End End If MsgBox( "Username/password Salah." & vbCrLf & _ "Silahkan cek lagi!" ) End If Catch ex As Exception MsgBox( "Error Login: " & ex.Message) End Try End Sub Private Sub Cancel_Click( ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles Cancel.Click Me .Close() End Sub End Class Lalu-kemudian mari kita coba run login form nya: Saat kita klik OK sebelum mengisi Username akan timbul pesan: Saat kita klik OK sebelum mengisi Password akan timbul pesan: Jika kita salah mengiputkan username atau password maka timbul pesan: Jika pengisian username dan password benar maka login akan sukses. Jika kita melakukan kesalahan login sebanyak 3 kali maka aplikasi akan ditutup. Click here if you like this article. Sumber http://rani-irsan.blogspot.com