Imports System.Data
Imports System.Data.OleDb
Imports System.String


Public Class Login

    Dim sProvider As String = "Provider=Microsoft.Jet.OLEDB.4.0;"
    Dim sDataSource As String = "Data Source= E:\Code\VB\NewManagerSystem\DataBase\NewsManagerSystem.mdb"
    Dim sConnString As String = sProvider & sDataSource
    Dim WithEvents myCn As New OleDbConnection

    Private Property myDataSet As DataSet

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ' login new manager system
        ' retrieve current username and password
        Dim userName As String
        Dim password As String
        Dim Sql As String

        userName = UsrNameText.Text
        password = PsdText.Text

        Try
            myCn.ConnectionString = sConnString
            myCn.Open()
            'MsgBox("连接正确!!")
            ' open Password table to access
            Sql = "SELECT * FROM passwd"
            ' create data set
            myDataSet = New DataSet()
            ' get a data set
            Dim myCommand As OleDbDataAdapter = New OleDbDataAdapter(Sql, myCn)

            'Let Dataset bind Password table

            myCommand.Fill(myDataSet, " passwd")
            Dim bLogin As Boolean
            bLogin = False
            'verify curent value validate or not?
            If (Not myDataSet Is Nothing) Then
                For Each cRow As DataRow In myDataSet.Tables(0).Rows
                    If (String.Compare(userName, cRow.ToString(), True) = 0) Then
                        bLogin = True
                    End If
                Next
            End If

            If (bLogin = True) Then
                MsgBox("Login successfully")
            Else
                MsgBox("Login unsuccessfully")
            End If

            'close OleDbConnection
            myCn.Close()

        Catch ex As Exception
            MsgBox(ex.Message)
        End Try


        ' verify current username and password whether they fulfill condition.
        ' if it fulfills jump to main interface or prompt error information
        ' if the input times is more then 3. pop up error message and close current system.

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        ' quit new manager system
    End Sub

End Class