Eager to know Differences between .NET 4.0 and .NET 4.5 in High level in .NET and also differences in ASP.NET, C# also in these frameworks
Microsoft announced the intention to ship .NET Framework 4 on 29 September 2008. The Public Beta was released on 20 May 2009.
After the release of the .NET Framework 4, Microsoft released a set of enhancements, named Windows Server AppFabric, for application server capabilities in the form of AppFabric Hosting and in-memory distributed caching support.
.NET Framework 4.5 was released on 15 August 2012., a set of new or improved features were added into this version. The .NET Framework 4.5 is only supported on Windows Vista or later. The .NET Framework 4.5 uses Common Language Runtime 4.0, with some additional runtime features.
Metro-style apps are designed for specific form factors and leverage the power of the Windows operating system. A subset of the .NET Framework is available for building Metro style apps for Windows 8 using C# or Visual Basic. This subset is called .NET APIs for apps. The version of .NET Framework, runtime and libraries, used for Metro style apps is a part of the new Windows Runtime, which is the new platform and application model for Metro style apps. It is an ecosystem that houses many platforms and languages, including .NET Framework, C++ and HTML5/JavaScript.
In the .NET Framework 4.5, new asynchronous features were added to the C# and Visual Basic languages. These features add a task-based model for performing asynchronous operations.
In the .NET Framework 4.5, the following features have been added to make it simpler to write and maintain Windows Communication Foundation (WCF) applications:
For more information and access to reference links, please visit:
===========.Net 4.5 Poster=========
This answer may be late reply but it will be useful for seeing this topic in future.
The features of .NET framework 4.5 can be seen in the following link.
To summarize:
Installation
.NET Framework 4.5 does not support Windows XP or Windows Server 2003, and therefore, if you have to create applications that target these operating systems, you will need to stay with .NET Framework 4.0. In contrast, Windows 8 and Windows Server 2012 in all of their editions include .NET Framework 4.5.
- Support for Arrays Larger than 2 GB on 64-bit Platforms
- Enhanced Background Server Garbage Collection
- Support for Timeouts in Regular Expression Evaluations
- Support for Unicode 6.0.0 in Culture-Sensitive Sorting and Casing Rules on Windows 8
- Simple Default Culture Definition for an Application Domain
- Internationalized Domain Names in Windows 8 Apps
You can find the latest features of the .NET Framework 4.5 beta here
It breaks down the changes to the framework in the following categories:
You sound like you are more interested in the Web section as this shows the changes to ASP.NET 4.5. The rest of the changes can be found under the other headings.
You can also see some of the features that were new when the .NET Framework 4.0 was shipped here.
Here is a great resource from Microsoft which includes a high level features overview for each .NET release since 1.0 up to the present day. It also include information about the associated Visual Studio release and Windows version compatibility.
.NET Framework Versions and Dependencies
What is new in .NET Framework 4.5 & What's new and expected in .NET Framework 4.5:
differences in ASP.NET in these frameworks
Compare What's New in ASP.NET 4 and Visual Web Developer and What's New in ASP.NET 4.5 and Visual Studio 11 Beta:
Asp.net 4.0
Web.config
File Refactoring And for Asp.net 4.5 there is also a long list of improvements:
HttpRequest
handling differences in C# also in these frameworks
Go Through C# 4.0 - New C# Features in the .NET Framework and What's New for Visual C# in Visual Studio 11 Beta.
Edit:
The languages documentation for C# and VB breaking changes:
VB: Visual Basic Breaking Changes in Visual Studio 2012
C#: Visual C# Breaking Changes in Visual Studio 2012
Hope this help you get what are you looking for..