#!markdown

# Chapter 7 - Packaging and Distributing .NET Types

Most of this chapter is about creating apps and class libraries for deployment so .NET Interactive notebooks cannot be used for most code examples.

#!markdown

## Importing a namespace to use a type

#!csharp

using System.Xml.Linq; // XDocument

#!csharp

XDocument doc = new();

#!markdown

## Relating C# keywords to .NET types

One of the common questions I get from new C# programmers is, "What is the difference
between `string` with a lowercase s and `String` with an uppercase S?"

#!csharp

using System; // String

#!csharp

string s1 = "Hello";
String s2 = "World";

#!markdown

## Understanding native-sized integers

C# 9 introduced `nint` and `nuint` keyword alias for native-sized integers, meaning that the
storage size for the integer value is platform specific.

#!csharp

using static System.Console;

#!csharp

WriteLine($"int.MaxValue = {int.MaxValue:N0}");
WriteLine($"nint.MaxValue = {nint.MaxValue:N0}");

#!markdown

## Testing your class library package

#!csharp

#r "nuget:packt.csdotnet.sharedlibrary,6.0.0"

#!csharp

using Packt.Shared;

#!csharp

#nullable enable

Write("Enter a color value in hex: ");
string? hex = "00ffc8"; // or ReadLine(); 
WriteLine("Is {0} a valid color value? {1}",
  arg0: hex, arg1: hex.IsValidHex());

Write("Enter a XML element: ");
string? xmlTag = "<h1 class=\"<\" />"; // or ReadLine()
WriteLine("Is {0} a valid XML element? {1}",
  arg0: xmlTag, arg1: xmlTag.IsValidXmlTag());

Write("Enter a password: ");
string? password = "secretsauce"; // or ReadLine()
WriteLine("Is {0} a valid password? {1}",
  arg0: password, arg1: password.IsValidPassword());