ASP.NET 4.0 Beta1 - What’s new in System.Web.dll. Assembly outlook [whitepaper]

Michael — Wed, 20 May 2009 07:57:00 GMT

Introduction

This guideline provides detailed overview of System.Web assembly and the new classes and methods in ASP.NET 4.0, which were released with Visual Studio 2010 Beta1.

Document is subject to change – we are trying to find detailed information about all new stuff and update description column. Send us your comments and suggestion via this online form.

Description

ASP.NET 4.0 introduces several changes to the web assemblies and also merges several dlls that existed in .NET 2.0 - 3.5 SP1. For example, new features from ASP.NET 3.5 System.Web.Abstractions.dll and System.Web.Routing.dll are merged with System.Web.dll, under System.Web namespace.

Changes

Beta1 of ASP.NET 4.0 introduced 27 new classes/interfaces/enums and 22 modifications of the existing ASP.NET 3.5 SP1 functionality.

Take into account, that Beta1 doesn’t provide the complete list of the new features – they can add new stuff or remove existed one prior to the final release.

The latest document version is available there http://tinyurl.com/qr583j (PDF file)

ASP.NET Theme across all pages with XMLHttpRequest calls

Michael — Sun, 27 Jul 2008 14:43:20 GMT

ASP.NET Themes is very powerful feature, but some limitations exist when you are trying to apply Themes dynamically.

For the single page the way to apply theme is to use

Page.Theme = “<themeName>”;

inside the OnPreInit event, but if you try to apply theme for all pages across your site you have two solutions:

add this code to each of the pages
apply theme for master.page – and it’s where problem starts

ASP.NET master pages don’t support applying themes dynamically – only static support for the all site pages by setting attribute inside web.config.

But what to do if you need control which theme to apply and you don’t want to add code to every page of your site?!

The solution for this to create custom HttpModule, where apply theme for Page class inside PreRequestHandlerExecute event.

See the following code-snippet of the ThemeHttpModule

        1: public void Init(HttpApplication context)

       2: {

       3:     context.PreRequestHandlerExecute += context_PreRequestHandlerExecute;

       4: }

       5:  

       6: void context_PreRequestHandlerExecute(object sender, EventArgs e)

       7: {

       8:     HttpContext context = HttpContext.Current;

       9:     if (!(context.Handler is Page))

      10:     {

      11:         return;

      12:     }

      13:  

      14:     Page page = (Page)context.Handler;

      15:     

      16:     if ((page != null))

      17:     {

      18:         string themeName = "Default";  // get theme name from somewhere

      19:         page.Theme = themeName;

      20:     }

      21: }

Done. Now you have flexible control which theme to apply in realtime, extracting you theme names from config or from database.

But there is one case, I’d like point you attention – XMLHttpRequest calls.

If you have AJAX XMLHttpRequest direct calls - this code won’t work, because server returns you only portion of page, not the full page with header and body. And you can’t apply theme on partial pages.

To solve this you need to check if it’s partial request or not, inside your HttpModule. In case of ASP.NET AJAX you could use ScriptManager.IsInAsyncPostBack, but for the direct XMLHttpRequest calls you need to check the header for the Content-Type you are used when create the MSXML object.

Something like this

       1: // Don't apply theme for XMLHttpRequest calls, because you are getting part of the page, not the full page

       2: if (! string.IsNullOrEmpty(context.Request.ContentType))

       3: {

       4:     return;

       5: }

Now your themes will be applied only on pages, not the partial AJAX calls.

Mirror: ASP.NET Theme across all pages with XMLHttpRequest calls

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ASP.NET 4.0 Beta1 - What’s new in System.Web.dll. Assembly outlook [whitepaper]

Introduction

Description

Changes

ASP.NET Theme across all pages with XMLHttpRequest calls