Use Response.Write().

If you’re worried that might not bring your website to its knees reliably enough, be especially sure to use Response.Write in code that’s executed during partial postbacks. It’s that easy!

Emitting JavaScript probably comprises the vast majority of Response.Write uses in ASP.NET projects today. So for our purposes, let’s say that we really want to display a JavaScript alert window during a partial postback, from code behind. Using Response.Write, this is how the task would have been accomplished:

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Just a quick Highslide update.

The HighslideManager control now has a ControlBar property. If enabled (and it’s enabled by default), all zoomed images will have a control bar overlay.

I’ve included embedded CSS, images, and cursors for the default style, pictured above. However, custom styling can be obtained via the controlbar CSS classes.

Visit the Highslide JS .NET project page for more details and the download link for the new version.

Your wishes are my command. Highslide JS .NET now includes support for captioning. The captions can be specified using the Caption property of each HighslideImage control, and can be easily styled using CSS.

Also, ~ is now correctly replaced with the application path in path properties.

Visit the Highslide JS .NET project page for more details and the download link for the new version.

Postback Ritalin has been getting a lot of search hits intended to find a button disable technique for full .NET postbacks. So, this example is for all of you searching for a non-AJAX solution.

The trick is to use the OnClientClick and UseSubmitBehavior properties of the button control. There are other methods, involving code on the server side to add attributes, but I think the simplicity of doing it this way is much more attractive:

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My initial .NET server control version of Torstein Honsi’s Highslide JS .NET is now available. You can find it and information on implementing it at the Highslide JS .NET page here on my site.

For a quick video introduction of what the Highslide JS library is capable of, take a look at this basic demonstration:

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Update: Highslide JS .NET is available for download now.

I’ve been working on and off for some time to encapsulate Torstein Honsi’s excellent Highslide JS library into a .NET control. Finally, pending naming, it is ready for use. It should be available for download in the next couple days. Until then, here is a preview of it in action:

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Based on my experience using it in the wild and some great feedback from those of you that downloaded it, I’ve made a few updates to Postback Ritalin. Get it and enjoy.

If you haven’t seen Postback Ritalin yet, it’s an AJAX Toolkit control extender to automatically disable an UpdatePanel’s submitting control during partial postbacks and then re-enable them after the partial postback completes. More details are available on the permanent Postback Ritalin page.

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“where did you find documentation on the sender and event args objects in the PageRequestManager events?”

Lately, if I don’t hear that question at least a dozen times a week, I start worrying that something’s wrong with my contact form. I can understand why it would be a common question. The documentation we currently have for the JavaScript portion of the AJAX framework is on the light side.

To answer the question: I didn’t. However, I can show you something even better.

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“Click here to download this report in Excel (CSV) format.”

We’ve probably all implemented this functionality in ASP.NET applications at least several times. Any time you’re dealing with report data, it’s expected that the data be available for download. Unfortunately, AJAX makes this somewhat difficult. Since there is no traditional HTTP response, you have no context with which to send the file to the browser for normal download.

Enter inline frames (IFRAME). Probably one of the most under utilized HTML elements around, dynamically creating an IFRAME allows you to round trip an HTTP request and response without disrupting the AJAX-ness of your async postback. Since any browser that supports XmlHttpRequest supports IFRAMEs, it is as safe to use as AJAX is in the first place. This is a simple example of the technique, using a static list of files in a dropdown, but it could be adapted to more dynamic file creation scenarios easily.

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“To avoid duplicate credit card charges, only click the checkout button once!”

I’m always surprised at how many sites display a similar warning message on their final checkout page. Major sites. Between server side detection of multiple submissions and using OnClick to disable the submit button, there is no excuse for crossing your fingers and hoping your users don’t double click a submit button.

AJAX complicates the client side component of this equation. You can’t simply disable a button in the OnClick event, because the button will remain disabled in the case of a failed form validation or other exception. The optimal behavior is for the submit button to only be disabled during the async postback, and be re-enabled when the server side processing is completed. Using the AJAXToolKit, I’ve created a control extender to implement this functionality quickly and easily: Postback Ritalin.

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