Public Class EditBook

    Inherits System.Web.UI.Page

    Protected WithEvents Label2 As System.Web.UI.WebControls.Label

    Protected WithEvents Label3 As System.Web.UI.WebControls.Label

    Protected WithEvents Label4 As System.Web.UI.WebControls.Label

    Protected WithEvents Label5 As System.Web.UI.WebControls.Label

    Protected WithEventsbtnUpdate As System.Web.UI.WebControls.Button

    Protected WithEventstxtPrice As System.Web.UI.WebControls.TextBox

    Protected WithEventstxtAuthor As System.Web.UI.WebControls.TextBox

    Protected WithEventstxtBookName As System.Web.UI.WebControls.TextBox

    Protected WithEventscboAvailability As System.Web.UI.WebControls.DropDownList

    Protected WithEventsbtnCancel As System.Web.UI.WebControls.Button

    Protected WithEventsrfvBookName As System.Web.UI.WebControls.RequiredFieldValidator

    Protected WithEvents RequiredFieldValidator1 As System.Web.UI.WebControls.RequiredFieldValidator

    Protected WithEventslblMsg As System.Web.UI.WebControls.Label

    Protected WithEvents Label1 As System.Web.UI.WebControls.Label

#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

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

        'Put user code to initialize the page here

       ' Ensure the msg label is invisible on load

       Me.lblMsg.Visible = False

        If Not Page.IsPostBack Then

            ' Get a reference to the viewbooks page which invokes this webform

            Dim ViewBookRef As ViewBooks = CType(Context.Handler, ViewBooks)

            ' Grab the BookId from the form

            Dim BookId As String = ViewBookRef.BookId

            ' Instantiate our business tier objects required

            Dim BookObj As New BookServices()

            Dim AvailObj As New AvailabilityServices()

            ' Retrieve the Book being edited

            Dim BookDs As DataSet = BookObj.GetBooks(Convert.ToInt32(BookId), Nothing, Nothing, Nothing)

            ' Populate our form with the book info

            If Not BookDs Is Nothing Then

                With BookDs.Tables(0).Rows(0)

                   Me.txtAuthor.Text = .Item(BookDb.FIELD_AUTHOR)

                   Me.txtBookName.Text = .Item(BookDb.FIELD_BOOK_NAME)

                   Me.txtPrice.Text = .Item(BookDb.FIELD_PRICE)

                    ' Populate the availability drop down

                    Dim AvailDs As DataSet = AvailObj.GetAllAvailability()

                   Me.cboAvailability.DataSource = AvailDs.Tables(0)

                   Me.cboAvailability.DataTextField = AvailabilityDb.FIELD_AVAILABILITY_NAME

                   Me.cboAvailability.DataValueField = AvailabilityDb.FIELD_AVAILABILITY_ID

                   Me.DataBind()

                    ' Once the form is databound we can select the availability Id of the book in the dropdown

                   Me.cboAvailability.Items.FindByValue(.Item(AvailabilityDb.FIELD_AVAILABILITY_ID)).Selected = True

                    ' Add the BookId to the viewstate so we can retrieve it on the next postback

                   Me.ViewState.Add(BookDb.FIELD_BOOK_ID, BookId)

                End With

            End If

        End If

    End Sub

    Private Sub btnCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click

       Server.Transfer(WebPageNames.VIEW_BOOKS)

    End Sub

    '#########################################################################################################################

    ' Updates the book information to the database

    '#########################################################################################################################

    Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpdate.Click

        ' Our validation controls have already ensured the correct fields are populated

        Try

            Dim BizObj As New BookServices()

           BizObj.UpdateBook(Me.ViewState.Item(BookDb.FIELD_BOOK_ID), Me.txtAuthor.Text, _

                             Me.txtBookName.Text, Me.txtPrice.Text, Me.cboAvailability.SelectedItem.Value)

           Me.lblMsg.Visible = True

           Me.lblMsg.Text = "The book was updated successfully"

        Catch ex As Exception

           Me.lblMsg.Visible = True

           Me.lblMsg.Text = "There was an error updating the book"

        End Try

    End Sub

End Class