Validate image exists

[Guest]

I'm trying to write some code to validate if an image is present on the
server. If the image is missing then I want to display out noimage.gif file.

I have a website that has thousands of products with thousands of images for
those products. Here's a page with two missing images.

http://dep.teamattire.com/Store/default.aspx?CatID=31&TeamID=45&SubCatID=75

Many of the images come from other webservers. We do not have the images
locally. I'd like to validate the image as the data grid loads (databound
event).

Any help or guidance is greatly appreciated.

Thanks!

 

[Rick Strahl [MVP]]

Generally this is a really bad idea because this will end up being very,
very slow.

What you might do is have some other process manage a table with the image
links and check them out and write them to a database. This works for either
file or URL based links. With URLs you can use WebClient to check
availability.

You can run this in an external process or fire off a separate background
thread from your ASP.NET application that manages this table of links. You'd
always assume last state until it changes. Obviously this will mean that the
data is not necessarily real time - it'll be only as up to date as the last
link run.

Another approach is have your application manage the image display
directly - have a link or something that can be resolved to a link in your
datagrid in your table that is used for item display and only fill this
value if the image is available. You can either auto-update that using the
same approach above or manually manage the image availabilty...

+++ Rick ---

--

Rick Strahl
West Wind Technologies
www.west-wind.com
www.west-wind.com/weblog

 

[Guest]

This would be ok however I get weekly datafeed that contain anywhere from
300,000 - 500,000 products each week. Granted a number of these will not
change however I have no idea which one will and which ones will not. I'm
planing on going down that route with the next site revision but will wait
until the next release of .NET comes out to do that. In the mean time I would
simply like to check for valid images.