I want to learn Xamarin on VS 2017. I can't find the same project as I see in most of all tutorials or guides. I have ".Net Standard" project and not Portable Class Library project. (see images).
[]
[]
I have installed all components of vs2017 but I can't see it.
[]
Why I can't see it? Are they the same?
(edit: the xamarin official site have 3 options, so I don't think they are)
Thanks
.NET Standard is the next evolution of Portable Class Libraries. Simply, they are PCLs but better. Choose a .NET Standard project and go through the tutorials as though you had used a PCL. When just starting out, you probably won't notice a difference until you start adding a lot of nuget packages.
Related
I decided to give Cross Platform Apps a go. I have been searching for tutorials for hours. A lot of them look interesting but i hit a problem at the start every time. Every tutorials tells me : File -> New Project -> Visual C# -> Cross-Platform -> Cross-Platform App (Xamarin.Forms). When i do this, i have to choose some settings, including "Blank App" and the Code Sharing Strategy. And that's where it goes wrong.
I should be able to choose Portable Class Library but it's not there. I can choose between "Shared Project" and ".NET Standard". Did I forget to install something or has the Code Sharing Strategy changed?
With Visual Studio 2017.5 they removed the option to create PCL option from the cross platform app. The standard class library is a better option than the PCL because the PCLs only allowed you to use the framework functions all the targeted platforms support. With standard libraries you have a list of functions it must support on all the platforms so you have much more available to you in the standard library than a PCL
I have PCL Library and I want to add it to standard (.net 4.6) C# console application. Everything is fine as long as I don't use any PCL specific classes inside the library. And if I do, I get an error "unsupported PCL profile". This error is not googlable. But the same library works fine in UWP application. I am searching for a solution or official explanation why I can't use PCL in non UWP application.
Yes you can. PCL is basically intersection of available API's across different platforms. The disadvantage is that the more target platforms you choose the smaller is the intersection:
Another disadvantage of PCL is that it generates separate assembly for each platform.
That's why Microsoft comes with .NET Standard - a replacement of PCL that uses different approach.
Think about .NET Standard as an interface, that defines set of API's. Then the platforms like .NET Framework, .NET Core, Xamarin.iOS, Xamarin.Android will implement the .NET Standard.
interface NetStandard1_0 {
}
interface NetStandard1_1 : NetStandard1_0{
}
interface NetStandard1_2 : NetStandard1_1{
}
net46: NetStandard1_6 {
}
dnxcode46: NetStandard1_6 {
}
As a result, you won't target specific platforms, but a version of .NET Standard instead. When your library targets .NET Standard, it can be used in any platform that implements the .NET Standards. Another advantage is you wont need separate assemblies for different platforms anymore. There will be single assembly that runs just everywhere.
However, I recommend you to wait until April 2017 when .NET Standrard 2.0 should be released. Microsoft promised that all platforms (.NET Framework, .NET Core, Xamarin.iOS, Xamarin.Android) will support this version of .NET Standard and it will have official support in Visual Studio. Also, Visual Studio projects using project.json will be converted to .csproj, so all Visual Studio projects will use the same format and it will solve a lot of compatibility issues. Cleanning of the mess that appeared in .NET last years was absolutelly necessary
Sure you can.
Just add .NET 4.6 to selected platforms:
It's appears at time when you create PCL.
More information here:
Cross-Platform Development with the Portable Class Library
Or you can change platforms in existing PCL. Just go to properties page and you will see:
Here is a good blog post about how to call UWP API from desktop App:
How to call UWP APIs from a desktop VB/C# app
I want to develop a small library which will be used across different C# projects.
I was looking at this guide - https://github.com/LRPalacios/net-core-get-started
It talks about creating a Class Library (.NET Core).
However, my copy Visual Studio Community 2015 does not show this option at all.
Only relevant thing I see is Windows Desktop -> Classic Desktop -> Class Library .
What is the difference and what is the best way to create a class library for use across different C# projects. My library won't have any UI elements.
Also, is dll the only way to go - is there a concept of static libs in dotnet?
To fix the .Net core project type issue, you have to install Visual Studio Update 3 and then install .Net Core Tools for Visual Studio.
You can of course use the current Class Library project but this will work only against the Full .Net framework project not .Net core alone
I read up on the new .NET Platform Standard concept replacing the old Portable Class Libraries, which seems nice. However, I can't seem to figure out how to create such a library, yet.
Is there a Project Template for Visual Studio where I could choose the target generation / netstandard? Or do I have to manually change a PCL project.json file for this?
(Got VS15, Update 3 installed)
If you create a PCL project and then double click properties, you should see an option to change your target platform. That will let you choose a .net standard version. Same thing as doing it yourself in the project.json but is the closest thing I have found so far to having a VS template do it for you
You can follow this Create .NET Standard Packages with Visual Studio 2015
From the article:
This guide will walk you through creating a nuget package targeting
.NET Standard Library 1.4. This will work across .NET Framework 4.6.1,
Universal Windows Platform 10, .NET Core, and Mono/Xamarin.
On Visual Studio 2019 it is possible to create projects that target .NET standard, just as you create another type of project. To do so, you just need to add new project, and then if you search for .net standard it will show several types of projects in which you can target .NET standard, as shown below.
You can also create new .NET Platform Standard projects from a template by using Visual Studio 2017 RC.
To be clear, I follow the MVVM pattern, and I want to structure my project such that I can share my model code between a UWP app and a standard WPF app. The code I want to share has no UI. I don't relish the thought of finding new tools to replace the ones that I've been using for years that take care of certain tasks like logging, connecting to a document oriented database, etc.
I attempted to start writing a UWP wrapper around some code I already have and reference the model project directly. Visual Studio refused to let that happen, showing me an error message that says "Unable to add a reference to project 'ACK.Model'". The same thing happened when I attempted to put the model in a Universal Library and reference it from a WPF app. I'm not trying to share WPF code. Just the model layer that has no reference to UI libraries.
This is a scary proposition, because it means that if I want to do anything substantial I have to choose to either jump 100% to UWP or stay 100% WPF. NewtonSoft.JSON might have a universal distribution (ASP.NET MVC), but what about ElasticSearch.NET, and other tools needed to make important apps?
I found where the "Portable Class Library" project type was hiding. PCLs will allow me to share my code across WPF and Universal apps as that was one of the options. This solves the simple case of the Model part of my code, but I (still) can't use some of the libraries I want. There are still a large number of libraries that I need that do not have PCL available.
About a year later, with the advent of Visual Studio 2017 there is a more complete solution. If you target your libraries to .Net Standard then the library is compatible with both .Net Core apps and the monolithic .Net targeted app. The support for standard .Net libraries and APIs is fairly complete, as is the support for modern C# language features.
The general advice now is this:
Target .Net Standard for all libraries
Target the appropriate platform for your actual application. (UWP or WPF).
NOTE: if your library has to interact with C libraries or applications, you have to take extra care to make sure you load the correct version.
It appears that there is a solution, but it has to be adopted by the whole tool chain you want to use. When Microsoft introduced Windows Store apps in Windows 8, they also introduced a Portable Class Library (PCL). The purpose of the PCL is to share code between different parts of your application.
When you create a PCL in Visual Studio 2015, you can specify the types of APIs you want it to be accessible from:
Universal Apps
Mono
.Net Core 5
.Net 4.6
This of course, limits the APIs available to you but most of the ones you want to use are OK as long as it's not UI related. There are other limitations as well:
Your project can only be edited in Visual Studio 2015 or greater
You don't have access to special directories from the Environment variable (i.e. user Documents directory, etc.)
You can't link to a library designed for only one of your target platforms (i.e. libgit2sharp, etc.)
There's no way to browse the API for this subset--MSDN needs to get on the stick. MSDN has updated much of the API documentation, but it's still difficult to figure out what applies to your PCL
However, you can link any library designed for a single target platform to your PCL. It's not ideal, but it's better than nothing.
The ASP.NET MVC stack has been ported to using PCLs, so you can use NewtonSoft.JSON directly as well as any other of those libraries used by that application. However, there are several libraries that have not been ported.
This arrangement forces you to think about how you want to integrate better. The .Net Core 5 seems to be stable, but support is in it's infancy. The current generation of Universal Apps as of VS 2015 update 1 uses .Net Core 5 directly.
There are several features from Nuget that are not currently supported even though work is under way:
MS Build extensions (major changes to MSBuild and the project.json structure)
Install/uninstall scripts (related to the removal of the concept of install)
Content (related to install/uninstall, but work is in progress on this)
Content transforms (related to lack of install/uninstall)
I wish I had a more complete answer. But this is as far as I got once I discovered the PCL and how it evolved for the current infrastructure.
I'm in the process of creating a game creation toolkit that incorporates version control right off the bat. I want to be able to deploy a game as a Windows 10 app, or as a standard WPF app, but due to the libraries I'm using to integrate version control I need to create the editor as a standard WPF app. I had to be a bit creative in building the shared code and importing the correct libraries.
First, my project hierarchy:
Project.Model (Portable Class Library)
Project.Model.Versioning (standard C# library)
Mvvm.Toolkit (Portable Class Library)
Editor (Standard WPF application)
I want the core PCL to be able to load a project and deserialize the JSON encoded objects. The PCL did have access to System.IO, but surprisingly it is not the same as the one defined in the standard C# library. Here's how I had to fix things:
After adding the package reference to NewtonSoft.JSON, I had to change the target framework in the packages.config file:
<package id="Newtonsoft.Json" version="8.0.2" targetFramework="portable-net452+win81" />
All projects dependent on my Project.Model class had to install the `system.io.filesystem' package from nuget so that the System.IO.FileInfo etc. objects were the same.
While this is definitely not a panacea, it's also not a dead end. I'm sure there are more gotchas, but this will at least help with some of the problems.
a .NET Standard library could be used to share a Model-View-ViewModel architecture between a WPF project and a UWP project.
https://www.syncfusion.com/ebooks/xamarin-forms-succinctly/sharing-code-among-platforms
https://devblogs.microsoft.com/dotnet/announcing-uwp-support-for-net-standard-2-0/