为Xamarin项目编译C＃库

Question

I'm pretty new to Xamarin and the whole C#/.NET world. I'm planning to develop a cross plateform app using Xamarin, and I will need to create libraries to share with others developers. I've heard of PCL, but some of the limitations bug me a bit. For exemple, I can't use System.Net, even if I can use it directly in an iOS or an Android project.

I know that, again for exemple, System.Net is compile differently in an iOS project than in an Android project, and that's one of the reason I can't use it in a PCL. However, is it possible to write a library, and then compile it for each plateform?

Shared projects, on the other hand, let me do it. But I can't share it as a library.

So, what I'm trying to do is to have only one code to maintain. Write once, compile twice, run everywhere (on mobile, except Windows Phone).

So, the question is :

Is it possible to achieve such a thing?

Answer 1

In our Desktop/Android/IPhone projects we used next approach:

Assume we have next projects

• Droid
• Touch
• Common.PCL
• Common.Shared

Droid and Touch projects reference PCL and Shared libraries. Next, create an interface in Common.PCL

namespace Common.PCL
{
    public interface INetSpecificFactory
    {
        INetSpecific CreateSomething();
    }
}

and implementation of it in Shared

using Common.PCL;

namespace Common.Shared
{
    public class NetSpecificFactory : INetSpecificFactory
    {
        public INetSpecific CreateSomething()
        {
            ....
        }
    }
}

Add autofac module in Shared library

using Common.PCL;
namespace Common.Shared
{
    public class AutofacModule : Module
    {
        protected override void Load(ContainerBuilder builder)
        {
            builder.RegisterType<NetSpecificFactory>().As<INetSpecificFactory>();
        }
    }
}

So, I can use INetSpecificFactory in my PCL via DI. It's better than use link files (it was one of the options at first)

Answer 2

What you could do is use compiler directives to differentiate which platform you are developing for.. unfortunately this does not reduce the fact to write different code twice for the different platforms as you need different libraries doing the same stuff on the different platforms.

With these directives you could compile each or your own library for the specified platform.

Answer 3

.NET Core and .NET Platform Standard are coming and you should check them out. They are the future to replace PCL.

I have already ported #SNMP Library partially to .NET Core RC1 and hope migrate the rest when RC2 and later come,

https://blog.lextudio.com/2016/03/how-to-port-snmp-library-to-net-core/

Answer 4

What you should do is creating a Class Library for both iOS and Android. Then, you write your code in only one of them, and link the code files to the other Class Library. That way, you're writing your code once, compile each Class Library and you get 2 DLL library from the same code.