asp.net check if imageURL exists

Question

I am trying to get a user's thumbnail from another intranet site but some of them do not follow the pre-defined format meaning I would want to load up a default thumbnail instead.

Whats the best way to check if an image URL is valid?

http://stackoverflow.com/questions/1588854/fallback-image-and-timeout-external-content-javascript there is the onerror attribute in the img tag — jjchiw, May 30 '12 at 09:01

Mike Miller · Accepted Answer · 2012-05-30T09:40:36.373

11

Depending on how you are getting your images a variation of this might work

<html>
    <body>
        <img src="<dynamic handler url>" alt="My Username" onError="this.src='defaultProfile.jpg';" />
    </body>
</html>

This is how you would do it in ASP.NET.

Designer -

<asp:Image ImageUrl="NonexistentImage.Jpg" ID="profileImage" Height="50" Width="50" runat=server />

Code Behind (c#)

profileImage.Attributes["onerror"] = "this.src='http://www.cs.uofs.edu/~olivetoj2/blah.jpg';";

This works perfectly for me.

edited May 30 '12 at 09:40

answered May 30 '12 at 09:03

Mike Miller

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Thanks. I will try this. the does not have this attribute. – sd_dracula May 30 '12 at 09:11
you can set it by adding it to attributes collections, http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.webcontrol.attributes.aspx – Mike Miller May 30 '12 at 09:16
onError doesnt seem to work for either or it actually said onError is not a valid element of – sd_dracula May 30 '12 at 09:29
It isn't part of the w3c standard but most browsers support it. Even back in 2001 - http://lists.w3.org/Archives/Public/www-html/2001Sep/0084.html. There are a lot of people using it (http://blog.sociomantic.com/2010/07/html-onerror-the-good-the-bad-and-the-ugly/) so it's likely to be the asp image control causing the issue. – Mike Miller May 30 '12 at 09:35
That works perfectly. I just had some syntax errors within the string. Thank you. – sd_dracula May 30 '12 at 09:59
No worries, probably should have put the asp.net example first. – Mike Miller May 30 '12 at 10:01
1

ASP VB code behind hide image if not found. myImage.Attributes("onerror") = "this.style.visibility=""hidden"";" – Brent Dec 10 '13 at 14:11

score 2 · Answer 2 · answered May 30 '12 at 08:59

2

WebRequest webRequest = WebRequest.Create(url);  
WebResponse webResponse;
try 
{
  webResponse = webRequest.GetResponse();
}
catch //If exception thrown then couldn't get response from address
{
  return 0;
} 
return 1;

answered May 30 '12 at 08:59

bilagi

21
1

You have forget to close the response objects and this lead to problems. – Aristos May 30 '12 at 09:01

score 2 · Answer 3 · answered May 30 '12 at 09:03

2

You can acheive this in jQuery quite easily.

$("#myImage")
    .load(function() { alert("it loaded ok") })
    .error(function() {  $(this).attr("src", alternateImage)  });

answered May 30 '12 at 09:03

Jeff Watkins

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score 0 · Answer 4 · edited May 31 '12 at 05:40

0

From the code-behind check

File.Exists(Server.MapPath("file path"))

If it returns true then assign the value, otherwise assign your default thumbnail.

edited May 31 '12 at 05:40

Matthias

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answered May 30 '12 at 09:06

dotnetmirror.com

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asp.net check if imageURL exists

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