'************************************************************************************
'@author : Jagriti
'@version : 1.0
'Development
Environment : MS Visual Studio.NET
'Name of the
File : ImgForm.aspx.vb
'Creation/Modification
History :
'
17-Feb-2003 Created
'Overview:
'This file
contains code that demonstrates how LOBs can be updated
'using ODP.NET
LOB objects. This webform is called from "Products Form". When this
'form gets
control then if the corresponding image for the selected product is
'existing it
appears in the "existingPicImageBx". To update the product's image
'the user can
select a new image by clicking the "Browse" button. To load this
image
'into
"newImagePicBx" the user can click "Load Image" button. To
update this image
'to database the
user can click "Save" button. Prior to updating the image,
'a transaction
is started. OracleDataReader is used to get the resultset for the
'Product
selected."GetOracleBlobForUpdate" is used to lock the row, it also
returns
'an updateable
LOB object of specified column for update. This BLOB object is
'assigned the
byte array for the new image chosen and the transaction is commited.
'***********************************************************************************
' Standard
Namespaces referenced in this sample
Imports System.Data
Imports System.IO
Imports System.Drawing.Imaging
' ODP.NET
specific Namespaces referenced in this sample
Imports Oracle.DataAccess.Client
Imports Oracle.DataAccess.Types
Public Class
ImgForm
Inherits System.Web.UI.Page
'UI components
Protected WithEvents existingImagePicBx As System.Web.UI.WebControls.Image
Protected WithEvents newImagePicBx As
System.Web.UI.WebControls.Image
Protected WithEvents Label3 As
System.Web.UI.WebControls.Label
Protected WithEvents Label4 As
System.Web.UI.WebControls.Label
Protected WithEvents CloseButton As
System.Web.UI.WebControls.Button
Protected WithEvents BrowseFile As
System.Web.UI.HtmlControls.HtmlInputFile
Protected WithEvents SaveBtn As
System.Web.UI.WebControls.Button
Protected WithEvents HeaderLbl As
System.Web.UI.WebControls.Label
Protected WithEvents LoadButton As
System.Web.UI.HtmlControls.HtmlInputButton
Protected WithEvents span1 As
System.Web.UI.HtmlControls.HtmlGenericControl
Dim imgURL As String
Dim ProdID, prodName As String
#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
'************************************************************************************
' This method is executed when the
page is loaded. If image for the selected product
' is exists then it is displayed.
'************************************************************************************
Private Sub Page_Load(ByVal sender As System.Object, ByVal
e As System.EventArgs) Handles
MyBase.Load
Try
' Get value for
"prodID" parameter
ProdID = Request.Params("prodID")
prodName = Request.Params("ProdName")
HeaderLbl.Text = "View/Update Image for Product :
" + prodName + " (" + ProdID + ")"
' Display existing image
If
(ConnectionManager.conn.ToString <> "") Then
LoadImage()
End If
Catch ex As Exception
Response.Redirect("Error.aspx?error=" +
ex.Message)
End Try
End Sub
'*************************************************************************************
' This code fires on the click event
of the "Save" button. The purpose of this code is
' to update LOB object using ODP.NET
LOB object.
'*************************************************************************************
Private Sub SaveBtn_Click(ByVal sender As System.Object, ByVal
e As System.EventArgs) Handles
SaveBtn.Click
Dim newImgUrl As String =
Session("imgurl")
Dim txn As OracleTransaction
Try
' Check if the user has
chosen an image using "Browse" button
If (newImgUrl <>
"") Then
' Start an Oracle
Transaction
txn = ConnectionManager.conn.BeginTransaction()
' Get datarow for
selected Product ID
Dim printmediaCmd As OracleCommand = New
OracleCommand("SELECT product_id, ad_image " & _
" FROM PrintMedia WHERE " & _
" product_id =" + ProdID, ConnectionManager.conn)
Dim
printmediaDataReader As OracleDataReader =
printmediaCmd.ExecuteReader()
Dim recExist As Boolean =
printmediaDataReader.Read()
If recExist Then
' Use
'GetOracleBlobForUpdate' to lock the row for updatation, 'orablob' is
' opened in an
updateable mode
Dim orablob As OracleBlob =
printmediaDataReader.GetOracleBlobForUpdate(1)
' providing read
access to the file chosen using the 'Browse' button
Dim fs As FileStream = New
FileStream(newImgUrl, FileMode.Open, FileAccess.Read)
' Create a byte array
of file stream length
Dim adImageData(fs.Length)
As Byte
' Read block of bytes
from stream into the byte array
fs.Read(adImageData, 0,
System.Convert.ToInt32(fs.Length))
' Writing byte array
to OracleBlob object
orablob.Write(adImageData, 0, fs.Length)
fs.Close()
' Commit transaction
txn.Commit()
End If
'On successful updation,
display the image in "exisitingImagePicBx"
'and clear the
"newImagePicBx"
If (newImgUrl
<> "") Then
'Show the image in
picture box
existingImagePicBx.ImageUrl =
Session("imgurl")
'Clear contents
newImagePicBx.ImageUrl = ""
End If
'Reset variables
newImgUrl = ""
'Display message on
successful data updatation
Response.Write("<b>Data saved
successfully</b>")
Else
Response.Write("<b>Select an image for
the advertisement!</b>")
End If
Catch ex As Exception
' Rollback Transaction in
case of failure
txn.Rollback()
Response.Redirect("Error.aspx?error=" +
ex.Message)
End Try
End Sub
'***************************************************************************
' The purpose of this method is to
display existing image for the product id
' selected.
'***************************************************************************
Private Sub LoadImage()
Try
'Clear contents
existingImagePicBx.ImageUrl = Nothing
newImagePicBx.ImageUrl = Nothing
If (ProdID <>
"") Then
' Use GetImage.aspx file
to return image
imgURL = "GetImage.aspx?productid=" +
ProdID
existingImagePicBx.ImageUrl = imgURL
End If
Catch ex As Exception
' Error Handling
Response.Redirect("Error.aspx?error=" +
ex.Message)
End Try
End Sub
'************************************************************************
' The purpose of this code is to load
image into "newImagePicBx" from the
' URL that is selected using
"Browse" button"
'************************************************************************
Private Sub LoadButton_ServerClick(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles
LoadButton.ServerClick
' If an image file is chosen
If Not
IsNothing(BrowseFile.PostedFile) Then
' Set the URL for
"newImagePicBx" as the new chosen image
newImagePicBx.ImageUrl = BrowseFile.PostedFile.FileName.ToString()
' Maintaining session state
Session("imgurl") =
BrowseFile.PostedFile.FileName.ToString()
End If
End Sub
'**********************************************************************
' On click event of close button,
navigate back to "ProductForm.aspx"
'**********************************************************************
Private Sub CloseButton_Click(ByVal sender
As System.Object, ByVal
e As System.EventArgs) Handles
CloseButton.Click
Response.Redirect("Productform.aspx")
End Sub
End Class
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