Check If An Image Is A GIF Specifically Images With Changed Extensions?
Apr 30, 2010
I've taken over work for the custom forums that a previous developer created at my job, and came across a minor bug. We don't allow animated GIFs as avatars in the forums. However, if someone were to take an animated GIF, rename it to imagename.jpeg, and then upload it, the forums will show the image as being animated.
It's a very odd bug as I didn't even think it played the animation if the extension wasn't .gif.
So my question is: Is there a way to check (in .NET 2.0) if an image is an animated gif, even if the extension isn't?
I am in the process of moving all of the images in my web application over to a CDN but I want to easily be able to switch the CDN on or off without having to hard code the path to the images. My first thought was to add an HttpHandler for image extensions that depending whether a variable in the web.config (something like ) will serve the image from the server or from the CDN. But after giving this a little though I think I've essentially ruled this out as it will cause ASP.NET to handle the request for every single image, thus adding overhead, and it might actually completely mitigate the benefits of using a CDN.
An alternative approach is, since all of my pages inherit from a base page class, I could create a function in the base class that determines what path to serve the files from based off the web.config variable. I would then do something like this in the markup:
<img src='<%= GetImagePath()/image.png' />
I think this is probably what I'll have to end up doing, but it seems a little clunky to me. I also envision problems with the old .NET error of not being able to modify the control collection because of the "<%=" though the "<%#" solution will probably work.
i have a textbox and a button.when the page loads, the textbox text read "hello"now when a user changes the text and then presses the button which causes a postback, how can i check if the user changed the value of the textbox or not?
I'm not sure whether or not this is the correct forum...I have been asked to develop a webpage with a very simple table. 10 columns, 10 rows. Each cell will have a dropdownlist. Several people will have this page up at any given time and they will all make changes as needed. I am planning on using a SQL Server 2008 database to keep track of the entries.I need the page to verify the data it contains against the data in the database every 5 seconds or so. If they are different, either the page can refresh or (if possible) the dropdownlist can just change to the correct value.
I am using telerik control to implement my project. For the validation i use asp.net validation controls. Now i need to check duplicate name for name field in the database. I have 2 options1. in the save button click event or custom validator2. after enter the name i can display the error.Here in the second option i have doubt. How can i achieve this ? using textchanged? i am using radtextbox. when i try textchanged some issues in validation controls because of ajax.I am using asp.net 3.5 So i got one new validator named Dynamic Validator. What is the purpose of this. i dint got any good articles to study abouyt this? Can i use this validator here. I read the following forum[URL]but not got any example for dynamic validator. I thought to implement the scenario like some registration form (yahoo) did.When username enterd just diaply duplicate
Note: The answer marked as the answer, answers the questions in the Title. However, my underlying problem, using type ahead dropdowns, is solved by moving to IE8.
I have a drop down list that when I CLICK a NEW selection I want to cause a postback ("this.form.submit()") But only if the click on the dropdown list just changed the selection.
Note that OnChange will NOT work because when the selection is changed by the keyboard I would not want to postback because it is a type ahead dropdown list.
I also suppose I could use OnChange and check if the change was caused by the mouse.
Maybe if we can come up with both solutions and i'll see which works better?
EDIT: More information:
AutoPostback = true; will not work. (don't want it to post back when the selection is changed by the keyboard)
onBlur = doPostBack; I tried this, but the result is not optimal. The user has to click off the ddl after making a selection with the mouse.
Another way to state what I want to do, i think, is do a postback when both the OnChange and OnClick events fire at the same time.
I want to display an image, be-able to drag small images on to the large image and then save the new image. Image having a photo as an image and wanting to put number blobs on and each number blob refers to a piece of text almost like labelling photo. I know how to drag and drop images using jquery but not sure how I would save the thing as a new image.
I have a requirement where image has to be uploaded to a folder and show it in image control. When uploading the image i have resized the image through code and saved it in a folder. The code is as follow
In my asp.net project, I have a view－image page and an upload－image page. I upload an new image and direct to the view page, the image doesn't be changed, because IE won't reload the image if the image's url remains the same. prefer the way to ask the browser to reload the image independently without server setting or web-headers changes.
In my asp.net project, I have a view－image page and an upload－image page. I upload an new image and direct to the view page, the image doesn't be changed, because IE won't reload the image if the image's url remains the same.
prefer the way to ask the browser to reload the image independently without server setting or web-headers changes.
I've got a working update panel which works fine when updating a label control, but I can't get it to work with an updated image (initial image loads fine - the problem is with the update). I think the problem maybe that the image name and location don't change, only the physical file. In other words, I've loaded the page, then updated the image (same name and location), but the image does not update with the label? Here's my code:
i test it in one page it work correctly but when i want use it in product.aspx page it didn't show image i think in my page there is some code that prevent to showing image from database but i can't find it
I have a website which loads images from a CDN. I have a requirement to check for the existence of 100s of images on the CDN.
I am using this code to achieve this:
Protected Function RemoteImageExists(ByVal Path As String) As Boolean Dim httpRequest As HttpWebRequest = CType(WebRequest.Create(Path), HttpWebRequest) httpRequest.Method = "HEAD" Try Dim httpResponse As HttpWebResponse = CType(httpRequest.GetResponse, HttpWebResponse) Catch ex As Exception Return False 'Undesirable flow, but seems unavoidable :( End Try Return True End Function
This is still very slow, and many requests timeout. Is there a faster way to do this?
I am knew to CSS I never usually do it. I am creating a menu and I change the image of the button when the button is hovered over it. But when I go on the submenu the image reverts back to the original image. The code I have used is below.
I just bought 2 months of godaddy hosting. I've written an ASP.NET MVC3 application using EF CodeFirst. In the application I am using an initializer that will drop/create the database if the model has been changed. I get an error when I try to do this saying "Cannot drop the database 'cellularautomata', because it does not exist or you do not have permission."I assume this has to do with the fact that I am on shared hosting and do not have permissions to drop/create databases. Is there any way around this?
I have a text field set up to accept a date: [Code]....
how to get the validator to make sure that the YEAR is acceptable. For instance, I can enter a year of "0000" and the validator will not catch it or display the error message. I can even enter a year of "9999" also. The only time the validator catches it is if I input something like "45/95/7589" for the date.
