'_____________________________________________________________-


'                       Introduction to Stream Reader in ASP.Net


'                                           Ron Kessler

'                                         Created 9/2/05
'_____________________________________________________________

'Updated 3/24/08

'Updates:
'   Updated to VS2005. This particular form is still using the VS2003 style so notice the
'   Windows generated code section in this form. 

'NOTES:

'If you want to listbox to work like you expect, then set the autopostback property=true
'features include,
'   How to make a message box on a web form
'   How to iterate through the controls collection
'   How to use stream reader
'   Introduction to the IsPostBack property
'   How to set the root path for the application
'   Reminder about formatting currency



'==================START OF CODE======================

Imports System.IO        'this adds streamreader class


Namespace LearningASP

    Partial Class Streams
        Inherits System.Web.UI.Page

#Region " Web Form Designer Generated Code "

        'This call is required by the Web Form Designer.
        <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

        End Sub


        Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
            'CODEGEN: This method call is required by the Web Form Designer
            'Do not modify it using the code editor.
            InitializeComponent()
        End Sub

#End Region

        Const TAXRATE = 0.075

        Dim rootPath As String = Server.MapPath("~")
        Dim FileName As String = rootPath & ("\items.txt")


        Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

            If Not IsPostBack Then
                Me.btnReturn.Attributes.Add("onclick", "return confirm('Are you sure you want to return?');")
            End If

            txtItem.Style("text-align") = "right"
            txtPrice.Style("text-align") = "right"
            txtQuantity.Style("text-align") = "right"
            txtSubTotal.Style("text-align") = "right"
            txtTax.Style("text-align") = "right"
            txtTotal.Style("text-align") = "right"

            GetItems()

        End Sub

        Private Sub btnLoad_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
            GetItems()
        End Sub

        Private Sub GetItems()


            '---we only want to read our data once so make sure it is inside the IsPostBack stuff
            If Not IsPostBack Then
                Dim MyReader As New StreamReader(FileName)
                Dim ItemInFile As String
                Dim Price As String
                Dim Product As String

                Try

                    Do

                        ItemInFile = MyReader.ReadLine()       'actual text in the file
                        Product = Trim(Left(ItemInFile, 10))    'the first 10 characters are the item
                        Price = Trim(Mid(ItemInFile, 20))         'starting at 20 we have the prices

                        '---add the product & price Product is text and price is the value. See items collection in the
                        'properties window for the listbox

                        lstItems.Items.Add(New ListItem(Product, Price))

                    Loop Until ItemInFile = Nothing


                Catch
                    lblError.Text = "I can't read the data file."
                    lblError.Visible = True

                Finally
                    MyReader.Close()
                End Try

            End If

        End Sub

        Private Sub lstItems_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lstItems.SelectedIndexChanged

            '---once the text property contains the item and the value property contains the price, grab them!
            txtItem.Text = lstItems.SelectedItem.Text
            txtPrice.Text = lstItems.SelectedValue

        End Sub

        Private Sub btnCheckOut_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCheckOut.Click

            Try
                lblError.Visible = False
                '---compute sub total
                txtSubTotal.Text = FormatNumber(txtPrice.Text * txtQuantity.Text)

                '---compute tax
                txtTax.Text = FormatNumber(txtSubTotal.Text * TAXRATE)

                '---amount due
                txtTotal.Text = FormatNumber(Convert.ToDecimal(txtSubTotal.Text) + Convert.ToDecimal(txtTax.Text))


            Catch
                lblError.Text = "Please make sure all data is entered correctly...."
                lblError.Visible = True

            End Try
        End Sub

        Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click

            '---iterate through the controls collection
            '---define (Dim) ctrl in the loop itself like this:

            'For Each ctrl As Control In Page.FindControl("Form1").Controls


            'or do it the regular way...

            Dim ctrl As Control
            For Each ctrl In Page.FindControl("Form1").Controls
                If ctrl.GetType() Is GetType(TextBox) Then
                    CType(ctrl, TextBox).Text = ""
                End If
            Next

        End Sub

        Private Sub btnReturn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReturn.Click
            Response.Redirect("default.aspx")
        End Sub
    End Class

End Namespace