Introduction to the C# Programming Language for the VB Programmer

Slide 2 Lecture Overview Compilation and execution of programs Some key terms Introduce the C# programming language for the VB developer Mention some important features of the Visual Studio.NET environment Pass along some editing tips and tricks

Slide 3 Program Compilation The.NET languages are compiled languages Code is compiled from the source language (VB, C#, etc..) into machine independent assembly language (MSIL) MSIL is converted to executable through JITing (Just in time)

Slide 4 Program Execution (1).NET applications use the Common Language Runtime (CLR) and are executed as Managed Code Libraries are stored in framework classes Your code and framework classes are executed by the CLR

Slide 5 Program Execution (2)

Slide 6 Fundamentals of.NET and C# (1) Unified type system (Common Type System) Unified run-time engine with memory management built-in (Common Language Runtime) (Garbage collection) It’s a type safe language Static types are enforced at compile time rather than at run time

Slide 7 Fundamentals of.NET and C# (2) Classes encapsulate functionality and have methods, properties (object orientation) Classes implement interfaces See Figure 1.1

Slide 8 C# Development and Runtime Model

Slide 9 Assemblies and Namespaces Assemblies are physical – Namespaces are logical An assembly may contain one or more namespaces The.NET Framework is just a bunch of assemblies Namespaces are organized into a hierarchy Namespaces are connected together with a dot (.) System namespace contains components developed by the.NET team Microsoft namespace contains components developed by Microsoft but outside of the.NET development team We references these assemblies and namespaces from our applications

Slide 10 Common Assemblies System.dll defines the primary data types System.Data.dll defines the components that make up ADO.NET System.Drawing.dll contains the components used to draw various shapes to an output device Forms and printers are output devices System.Windows.Forms.dll contains components to implement desktop forms System.XML.dll used to process XML documents

Slide 11 Common Namespaces System namespace contains fundamental classes System.Data namespace contains classes supplying data access capabilities ADO.NET System.Drawing provides access to the Graphical Device Interface allowing shapes to be drawn to forms and printers System.IO provides access to files System.Windows.Forms supplies the capabilities to create forms and control instances on those forms

Slide 12 Adding an Assembly Reference

Slide 13 Importing and Using Namespaces By default, you must fully qualify class and method names System.IO.StreamReader for example In VB, the Imports statement allows unqualified references Imports System.IO In C#, it’s the using statement using System.IO;

Slide 14 Project Structure Everything is the same as VB Solution file, project file, program files Namespace references Modules have a file suffix of.cs instead of.vb Application startup works a bit differently VB uses a form or Sub Main C# has a “special” procedure named Main()

Slide 15 Solution Explorer Shows all relevant project files

Slide 16 And now for the all Famous Hello World Create a new C# Console project

Slide 17 Program.cs using statements replace Imports statement

Slide 18 Program.cs namespace forms the outer block { } marks a block

Slide 19 Program.cs namespace blocks contain classes, which contain properties and methods

Slide 20 Program.cs The Main() method is called the entry point It’s where program execution begins Must be declared as static Method can return either a void or an int

Slide 21 Program.cs Methods (Main) contain local variable declarations and executable statements