Category Archives: C#

Update on C# and VB in VS2017

The latest version on Visual Studio 2017 at this moment is still in Release Candidate (RC) stage on build 26127.03, released on 1st Feb 2017. There are many new features in this VS2017 which it is too long to write all of them down here. You may visit the release notes for more detail.

Here I want to highlight the new support for C# & VB, and also 2 new members in VS2017, Visual Studio for Mac and Visual Studio Mobile Center.

Visual Studio for the Mac

is built from the ground up for the Mac and focused on full-stack, client-to-cloud native mobile development, using Xamarin for Visual Studio, ASP.NET Core, and Azure. To learn more, please read Miguel de Icaza’s blog post introducing Visual Studio for Mac.


Visual Studio Mobile Center

is “mission control for mobile apps.” It brings together multiple services commonly used by mobile developers into a single, integrated service that allows you to build, test, deploy, and monitor cloud attached apps in one place. To learn more, please read Nat Friedman’s post elaborating on Visual Studio Mobile Center.


OK, let’s talk about the new feature support for C# & VB in VS2017.

IDE Experience and Productivity

Visual Studio provides new refactorings to allow you to organize source code with one action:

  • New in RC Simplify object initialization with an initializer:
  • New in RC Move out variable declarations inline, leveraging a new C#7 feature:
  • New in RC Simplify null checks and throw expressions using null-coalescing operator, leveraging a new C#7 feature:
  • Move type to matching file: Extract a type from one file and put it in another file with a matching name with one click via Ctrl+..
  • Sync file and type name: If your file and type name are out of sync, you can use Ctrl+..
  • Convert String.Format to string interpolation: take advantage of the C# 6 language feature with this Quick Action.

This release also introduces improvements to IntelliSense that will make you more productive when working in a large solution or an unfamiliar codebase. We have added an icon tray to IntelliSense that enables you to filter the member list by type (e.g., methods, properties, classes, etc.). Each filter toggle has an associated keyboard shortcut which you can discover by hovering over the icon. To enable this feature, go to Tools > Options > Text Editor > [C# | Visual Basic] > IntelliSense and check the options for filtering and highlighting.

We’ve also added/updated style analyzers to help you customize and enforce coding conventions on your team, including:

  • Naming style rules.
  • Use of “var” or explicit types.
  • Use of “this.” or “Me.” on member access.
  • Missing braces.
  • Missing switch case.

New in RC Building on Visual Studio’s support for EditorConfig, we worked with the community to add .NET code style settings to the file format. This means that you can configure your team’s code style conventions, check them into source control, and have violations appear live in the editor as developers are typing. You can see all the code style options in the Roslyn repo’s .editorconfig or in the documentation.

Other new features in this release include:

  • You can now split a long string into multiple concatenated strings by positioning the cursor mid-string and pressing Enter.
  • A new code action for converting a property to a method.
  • We now use fuzzy matching in the NavigateTo search results.

Look for the following improvements to the IDE experience that are also in Visual Studio 2015 Updates:

  • A new quick fix option to add a reference to a NuGet package.
  • Refactorings that simplify delegate invocations and raising events using the null condition operator.
  • Refactorings to make async methods synchronous where applicable.
  • Improvements to Add Using command to support “fuzzy” matching for misspelled types, including adding any needed project or metadata references.

Language Extensions and Analyzers

This release includes some proposed new language extensions that we are working on for the next versions of C# and Visual Basic. These new language features are enabled by default and include:

For C#:

  • Task-like return types for async methods: This introduces the ability to return any task-like type from an async method. Previously these return types were constrained to Task<T> and Task.
  • Value tuples introduce language support for using tuples to temporarily group a set of typed values. To learn more, please review the design notes on GitHub.
  • Nested local functions extend the language to support declaration of functions in a block scope.
  • Pattern matching extensions enable many of the benefits of algebraic data types and pattern matching from functional languages.
  • Ref returns enable functions to return values by reference.

For Visual Basic:

  • Value tuples introduce language support for using tuples to temporarily group a set of typed values: Dim point As (x As Integer, y As Integer) = GetOffset().
  • ByRef return consumption extend the language to support consumption of functions and properties from libraries which have ByRef returns.
  • Binary literals and digit group separators allow native representation of binary numbers. This is super convenient for bitmasks and flags enumerations: &B1001_0011.

For more information, follow our development on GitHub to learn more about these and other proposed language extensions and APIs.

Finally, we have done considerable work to improve responsiveness of the IDE in presence of background operations that compute diagnostics and CodeLens information.

Bootstrap 3 Datepicker (eonasdan) does not work with jQuery 3.0 or above

if you are developing MVC, and you might have chance to look for a DateTimePicker for your MVC project. One of the favorites DateTimePicker is “Bootstrap 3 DatePicker” developed by Eonasdan ( ). You may download and get it from Nuget. You may also install by using Bower, Rails, Angular, Meteor or manually. The latest version in Nuget is v4.15.35.1.


One of the dependency is the jQuery. I have installed the latest one jQuery v3.1.1 at the moment I am writing to this blog.

I have followed the sample code Eonasdan has provided but I could not make it working. After some searching, I found out that Eonasdan has developed it when jQuery was still in v2. And jQuery has some changes from v2 to v3. One of the changes is jQuery does not provide the object.count() for jQuery object. It is changed into object.length

So, now you could make some code changes to the bootstrap-datetimepicker.js and the DatePicker will be working again. There are 2 locations of code that you have to change. Just simply search for “count()” and replace it as “length”.

Hope that my blog will help you to fix it. And as I know, someone has also point this out to the GitHub and commit into a new branch. But Eonasdan has not yet merge it into the release branch. Let’s do this fix in our way before he release the fixed code so that we could get a corrected js from Nuget.


Set menu item to Active in MVC with BootStrap

Recent I start working on MVC with BootStrap for building the great Web UI. I am building a menu with several menu items and found out that it is not setting as “active” in the class of the item when a page is loaded.


By default the MVC template doesn’t add the active class to the “li” item in the menu. So I have to add the class=”active” to the “li” to indicate the active menu item.


Above is the code that is used for the actual menu that create the menu in the first screenshot. if you look at line 8, you will see the class=”active”, this is what makes the active menu item. In order for us to do this, we need to know what page is currently loaded and then apply the active class css to the corresponding “li” element. The best way to do this, is to create a HTML helper to handle this for us.

Now, let’s try to create a new folder in the project and called “Helpers”. Then add a new class named “HtmlHelpers.cs” (from my sample, I used KenLinHtmlHelpers). here we could create an extension method of the HtmlHelpers method. We do this by creating a static class.


As you can see, I have created 2 method, IsActive and IsActiveController. The only difference is, do you want to take Action into one of the input parameter. If you want to set class is active whenever it is in the specific controller, you could use IsActiveController. Otherwise, you may use IsActive if you want the active class only in exactly the specified Action and Controller. Please also note that, I am letting the activeClass and inActiveClass input as optional with a default value.

Now we could update our cshtml as below,


Look carefully on each “li” item now. There is a new HtmlHelper method to check and show if it is the active controller.  Please also look carefully, I have also called the method in line 9, for the parents of the dropdown Menu.

NOTE: You have to reference the class in the top of the view page that you are using the IsActive or IsActiveController method in. Just add the code as line 1 of the above screenshot.

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