Generating Good Quality Thumbnail Images in ASP.NET

Amit Choudhary

The text of this article is not in this database — only its details are. The old site it was published on is gone, but the Internet Archive kept a copy: Generating Good Quality Thumbnail Images in ASP.NET

C#ASP.NETImage ResizingC# Bitmap ClassGood Quality Thumbnail Images

8 Comments

Join the conversation! Your thoughts help the community grow.

John Hazin16y ago
Hi Amit here is the mark up call <asp:Image ID="imgThumb" runat="server" ImageUrl="ThumbnailHandler.ashx?VFilePath=~/documents/pF232167k8/test.jpg & Height=230 & Width=340" AlternateText="Thumbnailimage" /> here is the source for a test image: <img id="ctl00_CPHContent_rptUploadedDocuments_ctl01_gvDocs_ctl02_imgThumb" src="ThumbnailHandler.ashx?VFilePath=~/documents/pF232167k8/test.jpg & Height=230 & Width=340" alt="Thumbnailimage" style="border-width:0px;" /> I get the standard broken image. please help John
- lalit dhake15y ago
  Hi, It looks nice article, but as i implement it, it is not working for me. infact I am trying this in asp.Net MVC . but :( please help
John Hazin16y ago
Hi Amit. Thanks your for help. how did you register the handler? What do I add in the web.config file if anything? or Is it done in IIS 7? Thanks. John
Amit Choudhary16y ago
hi john, IsReusable is an Menthod of IHttpHandler interface and we need to implement. ya i forget to mention it here. It will be like this: public bool IsReusable { get { return false; } } 2. User the handler with your Hyperlink like this: <asp:HyperLink ImageUrl='<%#"ThumbnailHandler.ashx?VFilePath=~/documents/"+Eval("folder")+"/"+Eval("filename")+"&Height=230&Width=340"%>' ................./> if it won't work then put an <asp:Image ImageUrl='<%.....%>' ../> between opening and closing tag of <asp:HyperLink....> // here you image goes</asp:HyperLink> Hope all your issues solved now.
- John Hazin16y agoedited
  Hi Amit, Thanks a tons for the help and the response. My errors are gone but it still doesn't work. I not sure when it should work. what I mean is should the thumbnail pop up when I hover over the hyper link? That is the effect I'm after. When I try this: <asp:HyperLink ID="hyprGridDocLink" runat="server" Text='<%# Eval("filename") %>' NavigateUrl='<%# "~/documents/" + Eval("folder") +"/" + Eval("filename") %>' Target="_blank" ImageUrl='<%#"ThumbnailHandler.ashx?VFilePath=~/documents/"+Eval("folder")+"/"+Eval("filename")+"&Height=230&Width=340"%>'> </asp:HyperLink> I get a broken link and nothing happens when I hover over the link. When I try this: <asp:HyperLink ID="hyprGridDocLink" runat="server" Text='<%# Eval("filename") %>' NavigateUrl='<%# "~/documents/" + Eval("folder") +"/" + Eval("filename") %>' Target="_blank" > <asp:Image ID="Image1" runat="server" ImageUrl='<%#"ThumbnailHandler.ashx?VFilePath=~/documents/"+Eval("folder")+"/"+Eval("filename")+"&Height=230&Width=340"%>' /> </asp:HyperLink> The hyper link text displays fine but again nothing happens when I hover over the link. I forgot to mention the hyper link resides in a gridview that resides in a repeater, will that be an issue? Thanks John
- John Hazin16y ago
  Hi Amit; Just as note I tried putting the code in the onmouseover of the hyper link but sadly no luck. thanks John
- John Hazin16y ago
  One more thing? Do i need to register the handler? Thanks
John Hazin16y ago
Hi Very Nice article. However I"m having to issues 1- when I compile I get: Error 50 'ThumbnailHandler' does not implement interface member 'System.Web.IHttpHandler.IsReusable' D:\webprojects\eDENT\www\ThumbnailHandler.ashx 2- Instead of an image I'm using an ASP.Net hyperlink. Will this still work ? I get a tag is not formated well error. here is the markup <asp:HyperLink ID="hyprGridDocLink" runat="server" Text='<%# Eval("filename") %>' ImageUrl="ThumbnailHandler.ashx?VFilePath=" + '<%# "~/documents/" + Eval("folder") +"/" + Eval("filename") %>' + " & Height=230 & Width=340" NavigateUrl='<%# "~/documents/" + Eval("folder") +"/" + Eval("filename") %>' Target="_blank" /> Thanks a ton for any help john