Programming C#
Day 7: IEnumerable, Libraries and NuGet, work on the projects
- The IEnumerable interface
- creating Enumerators with
yield
- What are libraries?
- Creating (CLR) libraries with C#
- Package managers
- The NuGet package manager
- Overall project structure
The IEnumerable interface
IEnumerable allows us to iterate through classes- Our own implementation enables use of
foreach for user-defined classes
- opens way to LINQ requests
- an enumerator is used to go through the elements
-
- think about using a specialized version with
IEnumerable<T>
- Writing a whole Enumerator class to iterate through a user defined class can be lengthy
- In many cases only the method
GetEnumerator is needed.
- Here
yield can simplify our life as it creates an Enumerator.
- A library is a compiled binary
- The only difference to an executable is that no Main() is defined
- A library consists of types and functionality
- Using 3rd party libraries boosts our productivity
- There are great libraries written in C# or
- Libraries that just wrap native libraries
- We already use libraries if we use the .NET-Framework
Creating a library with C#
- In Visual Studio: Start, New Project, C#, Class Library
- Libraries are the most efficient way to re-use projects
- Libraries are to the OS as what classes are to C#
- They improve reusability and encapsulation
- MSIL libraries also contain meta-data for reflection
- Using external libraries is quite easy
- The hard part is maintenance and dependencies
- We have to keep them up-to-date and we might need other libraries
- This can get quite cruel, since where to get is not always trivial
- A package manager offers a solution to those problems
- Usually there is a database with libraries
- Adding a library will result in a check for the dependencies and installation of the required libraries
- NuGet is an open-source package manager for the Visual Studio
- It is so popular, that it has been integrated into the Visual Studio 2012
- Every external library is now on NuGet
- Easy to publish on the public NuGet feed or create own private feeds
- Big advantage: Project bound and easy updating
- Another advantage: Powershell integrated
Overall project structure
- Add external resources to your project(s)
- Use NuGet for external libraries
- Create own libraries if you want to re-use (non-UI) functionality
- Use resource files for data, like images, sounds, texts, ...
- Big advantage: They can be localized (German, English, ...)
- Use DRY: Don't Repeat Yourself
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