The way to tell if the page is in an AJAX call is to check the ScriptManager.IsInAsyncPostBack property. Sounds trivial. The only reason I am writting about that is the very common confusion with the Page.IsAsync property that has absolutely nothing to do with AJAX.

Login control has a FailureText property that holds the text to display to the user when a login attempt fails. What if you want to report errors before making an login attempt? For example, you may handle the LoggingIn event to check a "IsDeleted" flag on user record and, if it is set, provide an error "The user is inactive". How can you set the error text without making an login attempt? This code will do that: protected void LoggingIn( object sender, System . Web . UI . WebControls

This is a very common scenario. You develop your application in environment A. The production will run in environment B. There will be also a demo site in environment C and a test site in environment D. The environments may have different connection strings, account identities, custom application settings, whatever else you may or may not think of. You clearly need to give to every environment its own web.config file. Or modify the setting in run time depending on what environment the application

This can be trivial for those fluent in IIS and Windows security. Not so for regular developers who need to impersonate their applications in IIS. To get your application pool run under another user account, that user account needs to be a member of the IIS_WPG security group. Hope this will save someone hours of work.

Recently my Visual Studio started freezing for 1-3 minutes after every build, no matter successful or not, debug or release. Save All operation also became very slow. This was extremely annoying. Eventually, I found the culprit. My solution .suo file grew quite big. I just deleted it and all delays gone.

If you try using the ChangePassword control for changing several passwords on the same page, you will notice that after confirming successful password change the control always shows the same success message and doesn't offer any text entry fields any more. The reason is that the control maintains an internal state machine and doesn't reset it properly after succes password changes. The state machine is controlled by internal property CurrentView that is not available for direct setting.

A simple javascript will make your Enter key work as Tab. It is useful in large tabular forms. function enterToTab(){ if (event.keyCode==13) event.keyCode=9; } <input type="text" onkeydown="enterToTab()"> Note using onkeydown event. Onkeypress won't do the trick.

If you need to know if client's browser runs on a Vista machine, run javascript navigator.userAgent or navigator.appVersion and search the returning string for "Windows NT 6.0". If it is there, you are on Vista.

Soon you won't need to go to the server to treat your client-site javascript with some c# calls. Watch this technology, it looks promising: Silverlight . Scott Guthrie: Silverlight opens up a ton of opportunities to build significantly richer client experiences that run cross platform and cross browser. For .NET developers, it means that you can now write .NET code using any development language (VB, C#, Javascript, Python, Ruby and more) in the web-browser (using Silverlight), web-server (using

Ever tried to get a <table> to take the whole browser height? Not a trivial task if you want to keep the browser in the Strict mode. Yes, removing <! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> will do, but that's already the Quirks mode. This css rule will work even in the Strict mode: html, body, table#main {height: 100%}