Category Archives: C#

NuGet redirection and package retrieval errors in Visual Studio 2015

Yesterday I have experience that I tried to install NuGet Package but an error occurred while retrieving package metadata in Visual Studio 2015.


After getting some try and catch. I found out that the VS2015 is configured to connect the API v3 of the So I tried to add another one with the URL on API v2 of the and I am then able to install any NuGet package. So I think that if you hit into the same error, this is a good to try.




Useful links to learn Windows 10 and VS2015

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I am sure that you all are new to Win10 and VS2015. You may be looking for learning resource. Here I listed some of the sample site for you and so you could get some learning on these 2 new products.

Opportunity URLs Remarks
Developer Tools Download Download any Visual Studio skus, including VS 2015
Developer for Windows 10  -What’s New
Get Started
All the info developers may need to write apps
Windows 10 courses in MVA Great site to get online courses on Windows 10
Channel Another great online resource for Windows 10 related videos
Windows 10 Jumpstart A live event on August 14th

Visual Studio 2015 is released

As many of you might know that VS2015 is already released on 20th July 2015. If you are MSDN Subscriptor, you could download and install it now. For the Team Foundation Server 2015, you might have to wait for a little bit longer.

Watch the keynote on demand below to learn about the latest features and technologies. You can also watch the Visual Studio developer team create an end-to-end solution for an open-source project and see how they tackled problems along the way.

For more Visual Studio 2015 deep dive videos, please visit

To download Visual Studio 2015, please visit

For more information about Visual Studio 2015, please visit

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We got a promote code to give away and it allows you to take any online training for 21 days of free access.

The promo code to share is: HKNUGMSTC315

To use the Promo Code follow these instructions:

  1. Go to
  2. Click on the Sign up Now button.
  3. Select “Use Promo Code”
  4. Enter HKNUGMSTC315 in the Promo code box.
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New Feature for C# in VS2013? Nope.

As one of my previous blog “The new features introduced in each version for C# (1.0 – 5.0)“, I promised that I will come back to this when VS2013 is released. This time I come with more information about them.

.NET Framework versions

There have been seven significant releases of the .NET Framework, excluding service packs. The framework includes the compilers, runtime, and libraries. Additionally, there are other profiles such Silverlight which complicate matters.

  • 1.0 – released in 2002
  • 1.1 – released in 2003
  • 2.0 – released in 2005, with a new CLR (to handle generics and nullable types) and compilers for C# 2 and VB 8.
  • 3.0 – released in 2006, this is just 2.0 plus new libraries: Windows Presentation Foundation, Windows Communication Foundation, Workflow Foundation, and Cardspace
  • 3.5 – released in 2007, this is 3.0 plus new libraries (primarily LINQ and some extra “base” libraries such as TimeZoneInfo) and new compilers (for C# 3 and VB 9)
  • 4 – released in 2010, this includes a new CLR (v4), new libraries, and the DLR (Dynamic Language Runtime)
  • 4.5 – released in 2012, this allows for WinRT development on Windows 8 as well as extra libraries – with much wider async APIs

C# language versions

There are five significant language versions:

  • C# 1
  • C# 2, introducing generics, nullable types, anonymous methods, iterator blocks and some other more minor features
  • C# 3, introducing implicit typing, object and collection initializers, anonymous types, automatic properties, lambda expressions, extension methods, query expressions and some other minor features
  • C# 4, introducing dynamic typing, optional parameters, named arguments, and generic variance
  • C# 5, introducing asynchronous functions, caller info attributes, and a tweak to foreach iteration variable capture

See the specifications page for downloads for each version, from Microsoft and ECMA.

Visual Studio versions

For a long time, releases of Visual Studio were closely tied to framework releases. The picture has become a bit more flexible and complicated, however:

  • VS.NET 2002 – support for C# 1 and .NET 1.0
  • VS.NET 2003 – support for C# 1 and .NET 1.1
  • VS 2005 – support for C# 2 and .NET 2.0, and .NET 3.0 with an extension
  • VS 2008 – support for C# 3 and .NET 2.0, 3.0 and 3.5 (multi-targeting)
  • VS 2010 – support for C# 4 and .NET 2.0, 3.0, 3.5 and 4
  • VS 2012 – support for C# 5 and .NET 2.0 to 4.5 (including WinRT on Windows 8), and portable class libraries

That’s all the theory. Here are the practical limitations and working configurations. Note that this assumes you want to use Visual Studio – if you’re happy to use just the command line compiler, that’s a slightly different story which I’ll avoid for simplicity’s sake. (At some point I’ll return to this page to talk about C# 4 and C# 5 features, but not just now…)

  • You can’t use C# 2 features without at least VS 2005
  • You can’t use C# 3 features without VS 2008
  • You can’t ask VS 2005 or VS 2008 to target .NET 1.0 or 1.1 (there’s an extension for it, but I haven’t used it – expect some pain for debugging etc)
  • You can’t force VS 2008 to restrict you to only C# 2 features, or force VS 2005 to restrict you to C# 1 features
  • Each version of Visual Studio has its own project file format and will upgrade your older projects when you first load them in that version. (The differences between VS 2003 and VS 2005 were significant; the differences between VS 2005 and VS 2008 are much smaller.)
  • VS 2008 has special support (in project properties) for which framework version you want to target: 2.0, 3.0 or 3.5
  • You can use most C# 3 features when targeting .NET 2.0 or 3.0, but not quite all
Evolution of C# in vs2013
Evolution of C# in vs2013

You may found that there is no update on C# in VS2013. Yes, this is correct.

From the MSDN Developer Blog,
No new C# and VB Language Features in VS 2013

From the MSDN Library
What’s New in Visual Studio 2013

You may also have a look on the MSDN page for more information
.NET Framework Versions and Dependencies