Login asp.net หา Username &Password ไม่พบ คือนู๋ใช้ textbox รับค่า Username &Password จากผู้ใช้

Imports System.Data.Odbc
Imports System.Data
Imports System.Data.OleDb
Partial Class Login
    Inherits System.Web.UI.Page
    Dim conn As OdbcConnection
    Dim strcon As String
    Dim strSQL As String
    Dim a As Boolean = False
    Private Sub connectODB()
        strcon = "DRIVER={Microsoft Excel Driver (*.xls)}; IMEX=1; HDR=1;Excel 8.0; DBQ=D:\\nicha\\MachineList.xls"
        conn = New OdbcConnection(strcon)
        conn.Open()
    End Sub
    Protected Sub btnOk_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnOk.Click
        connectODB()
        Dim da As OdbcDataAdapter
        Dim ds As DataSet = New DataSet

        Dim i As Integer = 0
        If txtUser.Text = "" Or txtPass.Text = "" Then
            If txtUser.Text = "" Then
                MsgBox("Please Enter User")
            End If
            If txtPass.Text = "" Then
                MsgBox("Please Enter Password")
            End If
        ElseIf txtUser.Text <> "" Or txtPass.Text <> "" Then
            strSQL = "SELECT * FROM [Sheet2$] " ' WHERE username  = '" & txtUser.Text & "' " 'and pass = '" & txtPass.Text & "'"
            da = New OdbcDataAdapter(strSQL, conn)
            da.Fill(ds)
            GridView1.DataSource = ds.Tables(0)
            GridView1.DataBind()
            Do
                If txtUser.Text <> ds.Tables(0).Rows(i)(0) And txtPass.Text <> ds.Tables(0).Rows(i)(1) Then
                    a = False
                Else
                    a = True
                End If
                i = i + 1
            Loop While txtUser.Text = ds.Tables(0).Rows(i)(0) And txtPass.Text = ds.Tables(0).Rows(i)(1)
            If a = False Then
                MsgBox("Change Password")
            ElseIf a = True Then
                MsgBox("OK")

            End If
        End If
        conn.Close()

    End Sub
End Class