مساعدة في تجسيد فكرة - نسخة قابلة للطباعة

كود :

Module Module1



    Public con As New OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Database1.accdb")



    Public lastVisit As Date





End Module



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Public Class Form1



    Private Sub btnLogin_Click(sender As System.Object, e As System.EventArgs) Handles btnLogin.Click



        lastVisit = Nothing



        Using cmd As New OleDb.OleDbCommand("SELECT [LastVisit] FROM [Table1] WHERE ([UserName]=@un) AND ([Password]=@pw)", con)

            cmd.Parameters.AddWithValue("@un", txtUserName.Text)

            cmd.Parameters.AddWithValue("@pw", txtPassword.Text)



            If con.State <> ConnectionState.Open Then con.Open()

            Dim ret = cmd.ExecuteScalar

            con.Close()



            If ret IsNot Nothing Then



                lastVisit = ret



                cmd.CommandText = "UPDATE [Table1] SET [LastVisit]=Now WHERE ([UserName]=@un)"



                If con.State <> ConnectionState.Open Then con.Open()

                cmd.ExecuteNonQuery()

                con.Close()



                Form2.lblLastVisit.Text = "Last visit: " & lastVisit



                MsgBox("Last visit: " & lastVisit)



                Me.Hide()

                Form2.ShowDialog()

                Application.ExitThread()



            Else

                MsgBox("Username or Password not valid")



            End If



        End Using



    End Sub



End Class

كود :

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click



    Dim UserLogin As Boolean = False



    Using da As New OleDb.OleDbDataAdapter("SELECT COUNT(*) FROM [Table1] WHERE ([UserName]=@un) AND ([Password]=@pw)", con)

        da.SelectCommand.Parameters.AddWithValue("@un", txtUserName.Text)

        da.SelectCommand.Parameters.AddWithValue("@pw", txtPassword.Text)

        Dim dt As New DataTable

        If da.Fill(dt) > 0 Then

            UserLogin = True

        Else

            MsgBox("Username or Password not valid")

        End If

    End Using



    If UserLogin Then



        Using da As New OleDb.OleDbDataAdapter("SELECT * FROM [UserVisit] WHERE ([UserName]=@un)", con)

            da.SelectCommand.Parameters.AddWithValue("@un", txtUserName.Text)

            Dim dt As New DataTable

            If da.Fill(dt) > 0 Then

                Label1.Text = dt.Rows.Cast(Of DataRow).Last.Item("Visit")

            Else

                Label1.Text = "First visit."

            End If



            DataGridView1.DataSource = dt



        End Using



        Using cmd As New OleDb.OleDbCommand("INSERT INTO [UserVisit] ([UserName],[Visit]) VALUES(@un,Now)", con)

            cmd.Parameters.AddWithValue("@un", txtUserName.Text)

            If con.State <> ConnectionState.Open Then con.Open()

            cmd.ExecuteNonQuery()

            con.Close()



        End Using



    End If

End Sub