[Last Call] Learn about multicloud storage options and how to improve your company's cloud strategy. Register Now

x
?
Solved

Using an asp:UpdatePanel to Trigger vb code to save picture into a database

Posted on 2012-03-27
1
Medium Priority
?
518 Views
Last Modified: 2012-03-27
Hi,
I have a button and an input type=file box.  This uses some vb code to convert a picture so I can save it into a database image column.  This all works fine.  If I add an update panel around it with a asp:PostBackTrigger again it works fine but is still jumping for the user.  If I use a asp:AsyncPostBackTrigger it breaks on the following line.

intImageSize = File2.PostedFile.ContentLength

This is the error I recieve.

System.NullReferenceException was unhandled by user code
  Message=Object reference not set to an instance of an object.
  Source=App_Web_kxfoj2ur
  StackTrace:
       at Create_Brief.Button4_Click(Object sender, EventArgs e) in C:\Documents and Settings\newcoc01\My Documents\Visual Studio 2010\WebSites\20120327\Create_Brief.aspx.vb:line 550
       at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
       at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
       at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)
       at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
       at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
       at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
  InnerException:

 Protected Sub Button4_Click(sender As Object, e As System.EventArgs) Handles Button4.Click

        '**** Resize image section ****  File2
        Dim strImageType As String
        Dim intImageSize As Int64
        Dim ImageStream As Stream

        ' Gets the Size of the Image
        intImageSize = File2.PostedFile.ContentLength

        ' Gets the Image Type
        strImageType = File2.PostedFile.ContentType

        ' Reads the Image
        ImageStream = File2.PostedFile.InputStream

Open in new window


Does anyone know why this happens and how I can get this working?
0
Comment
Question by:morant
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 7

Accepted Solution

by:
Lalit Chandra earned 2000 total points
ID: 37772818
This problem is somewhat well documented, the update panel is listed as not working with certain controls.

File upload, and tree view being 2 of the biggies.

IN any case, one solution is available on code project:

http://www.codeproject.com/useritems/simpleajaxupload.asp

if you look around the forums and google, you can read more about the problem if your interested, but the code project solution should get you started.

Hope this will guide you to solve your problem.
0

Featured Post

Important Lessons on Recovering from Petya

In their most recent webinar, Skyport Systems explores ways to isolate and protect critical databases to keep the core of your company safe from harm.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article is meant to give a basic understanding of how to use R Sweave as a way to merge LaTeX and R code seamlessly into one presentable document.
This article will show, step by step, how to integrate R code into a R Sweave document
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…
In a recent question (https://www.experts-exchange.com/questions/29004105/Run-AutoHotkey-script-directly-from-Notepad.html) here at Experts Exchange, a member asked how to run an AutoHotkey script (.AHK) directly from Notepad++ (aka NPP). This video…
Suggested Courses

650 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question