Anatomy of Code snippets in Visual Studio for Mac

Code snippet is a shortcut that can be used to generate a code from a specific template. Example of a built-in code snippet:

Type cw and double press the Tab key will result in Console.Writeline();

Thats a pretty simple example, however we pressed only 4 keys instead of 19 (ignoring the autocompletion of IntelliSense). In more advanced cases it might be a code snippet to generate a BindableProperty or a simple property in a ViewModel that should notify the binding engine about updates. Sounds like we can increase our performance by letting the code snippets generate boring repetitive code for us.

Visual Studio for Mac is shipped with a default code snippets that can be used as a great example. Let’s take a look on the cw code snippet. First let’s open the editor by clicking on Visual Studio > Preferences > Text Editor > Code Snippets. Now select the cw code snippet under C# group:

Screenshot 2018-11-29 at 00.26.55

#1. Shortcut – is the shortcut we have to type in order to generate the code from the template. In this example it is cw (Console.WriteLine).
#2. Group – there are different available groups including F#, Python and Razor.
#3. Variables – on the screenshot #3 appear twice to demonstrate the definition of the $SystemConsoleWriteLine$ variable and its properties.
#4. Default – stands for the default value of the variable. Please note that in order to avoid confusion we should also provide a namespace.
#5. Function – we can apply built-in functions like GetSimpleTypeName("System#Console.WriteLine"). It will make sure to remove the namespace before Console.WriteLine if using System is already in place otherwise it will use the default value (#4). The list of supported functions can be found here.

The template is just a XML file that live in ~/Library/VisualStudio⁩/{version}/Snippets directory, which means that you can easily import and export code snippets that you create.

Earlier today I created a GitHub repository with a couple of handy code snippets for Visual Studio for Mac and especially for Xamarin. You are welcome to check and contribute by sharing your own code snippets!

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Immutable Models in MVVM

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Source: flickr/ Jeff Attaway

MVVM

The first M stands for Model – an implementation of the application’s domain model that includes a data model along with business and validation logic. Examples of model objects include repositories, business objects, data transfer objects (DTOs), Plain Old CLR Objects (POCOs), and generated entity and proxy objects.

definition source

Immutability

In object-oriented and functional programming, an immutable object(unchangeable object) is an object whose state cannot be modified after it is created. This is in contrast to a mutable object (changeable object), which can be modified after it is created.

definition source

Why bother?

Imagine the next simple situation, your application downloads a JSON,  deserialises it to an object and then presents the downloaded data. You would expect the downloaded data to be one-to-one to the data on the remote server, however the data can be accidentally or intentionally mutated. Continue reading “Immutable Models in MVVM”

Archiving your code

simple_comic_zip

Intro

Title of this blog post may sound very weird in 2018 while github / vsts / bitbucket are still up and running. However, it still seems to be very common to archive your solution and upload it to cloud or send it by email. Don’t ask me why, it is just still there.

The most painful and annoying mistake you can make is to include dependencies that can be easily downloaded or compiled code. Painful because it may significantly increase the size of the archive and annoying because you may have to download it for hours because of it. Continue reading “Archiving your code”

Visual Studio for Mac tips & tricks

Switching from old good VS (for Windows) to a new cool VS for Mac can be painful. Original VS was released in 1997 (according to wikipedia) while VS for Mac was released only in 2016. Yes, it is based on XamarinStudio which is built on MonoDevelop but it still has a long way to go in order to be close to it’s ancient relative.

In this article we will take a look on VS for Mac “hidden gems” that can optimize and smooth your workflow. All you have to do is to open Mac’s VS Preferences and read this article on the side.

Environment

Font

One of the very basic yet very important settings is the Font. While there is nothing bad using the default font, FiraCode could beautify your code and improve it’s readability by replacing sequences of characters by a single ligature.

The project repository on github contains detailed information on how to install it in your system. It’s also great because this font can be used almost everywhere.

Continue reading “Visual Studio for Mac tips & tricks”

User input validation in Xamarin.Forms

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One of the very common tasks that any mobile developer meets is validation of the user input. It can be an email, password complexity, length, not empty or any other sort of input validation. In this article we will try to find an appropriate light-weight and reusable solution, so let’s start!

Continue reading “User input validation in Xamarin.Forms”

Firebase authentication in Xamarin.Forms

Firebase Authentication (vert, light)

Integrating Firebase Auth in Xamarin.Forms is very easy and basic authentication flow implementation can be achieved under 20 lines of code. There is more work with settings than code writing. In this article we will:

  1. Configure Firebase app
  2. Create Xamarin.Forms application to authenticate users via Firebase Auth
  3. Create a .NET Core WEB API project to validate Firebase Auth token and return simple data

Continue reading “Firebase authentication in Xamarin.Forms”

Automatically converting PCL to .NET Standard 2.0 project

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Every time you create a new Xamarin.Forms project  in Visual Studio for Mac you have to manually convert it to .NET Standard. The conversion is very straightforward and can be done with just a few steps:

Hopefully one day VS team will take care of it, till then, I decided to automate this process and created an add-in/extension for VS for Mac – Mutatio.

Mutatio – in Latin means change, transformation or exchange.

Mutatio can convert newly created or existing projects. Please keep in mind that there might be NuGet packages that does not support .NET Standard 2.0, in this case you may see related exceptions.

In case you change your mind and you want to rollback, Mutatio is making a backup of all the files it modifying and deleting under the project’s root directory within mutatio_backup folder. So all you have to do is to copy the files back to your project and reload the solution.

One of the biggest challenges I met while development was related to reloading the project after conversion. Within VS for Mac after manually modifying the *.csproj under the right click menu of the project there will appear a Reload option, however I didn’t find a way to call this method programatically. Currently, the whole solution will be reloaded as a workaround. If you know how to solve the problem programatically I would really appreciate if you will share your knowledge by contributing or leaving a comment.

More details can be found on GitHub.