Introduction to C# Tom Roeder CS fa

Goals of the course Introduce C# language ECMA standard originally developed by MSR not just Java + C++ many extensions Introduce.NET framework future of Windows base of Microsoft’s C# implementation

Non-goals Teach you to program should be very comfortable writing OO code we will not cover much if any basic programming Introduce object oriented languages not even teach you OO style (except wrt C#) expected to write all code in OO style Give you a detailed grade S/U only even homework

S/U Details Requirements for the course come to lecture participate do three assignments Assignments are S/U will not be giving a detailed grade show me that you understand the concepts, and can write C# code All three assignments will be online soon must be completed by the end of the course

Administrative Details Class time MWF 12:20-1:10 office hours: W 10:30-12 or by appointment (4112 Upson) Prerequisites: CS 211/212 really: experience in OO coding/concepts Academic Integrity Do not submit work that is not your own minimum penalty: U in the course

Useful Tools Visual C# Express: Google “Visual C# Express” in Visual Studio: MSDNAA must be version 2005: we need C# 2.0 Mono: Open Source impl for Linux: not quite at 2.0 Rotor: Shared Source impl for Windows (through 2.0) Used to work on BSD / OS X, too

Useful Tools Portable.NET: yet another open source impl CMS: we will use this for homework turn on your notifications! Course Webpage: will post lectures online as well as any errata for the homework

CSUGLab You all will have accounts MSDNAA access: let me know if you don’t currently have it Visual Studio.NET 2005 should be installed there

Syllabus Syllabus (10 more lectures) C# constructs: 5 lectures Types, Delegates, Generics, Reflection, Iterators.NET Memory Management: 1 lecture Topics: 4 lectures C# 3.0, Threading, Security, MSIL, MSH

Quiz 1 Each class will begin with a quiz not for credit but for knowledge but I will collect them and see what you know Today’s quiz will be on prerequisites OO programming, mainly to do with Java If you don’t know Java, but do have OO experience, it’s OK talk to me after if you have trouble

What is.NET? A Framework in which to run code A Common Language Runtime (CLR) runs all programs C# compiles to Microsoft Intermediate Language MSIL runs on CLR Virtual Machine like Java code written in many languages compiles to MSIL A Common Language Specification (CLS) A Common Type System (CTS)

What is.NET? Runtime Operating System.NET Framework Common Type System Common Language Runtime Building Blocks (e.g. for Services) Services:.NET and COM+ SQL ServerBizTalk... Languages : C#, Visual Basic, etc.NET Applications Enterprise Servers... Sharepoint... Web Services From MSDN

What is the CLR? Class Loader MSIL to Native Compilers (JIT) Code Manager Garbage Collector (GC) Security EngineDebug Engine Type CheckerException Manager Thread SupportCOM Marshaler Base Class Library Support From MSDN

What is the CTS? A set of common types any language that runs in CLR should implement no syntax specified Languages often define aliases For example CTS defines System.Int32 – 4 byte integer C# defines int as an alias of System.Int32

What is the CTS? From MSDN

What is the CLS? A specification of language features how methods may be called when constructors are called subset of the types in CTS are allowed For example Code that takes UInt32 in a public method UInt32 is not in the CLS Can mark classes as CLS-compliant not marked is assumed to mean not compliant

The Class Libraries The common classes used in many programs like Java Class Library eg. System.Console.WriteLine XML, Networking, Filesystem, Crypto, containers Can inherit from many of these classes Many languages run on.NET framework C#, C++, J#, Visual Basic even have Python (see IronPython)

Assemblies Code contained in files called “assemblies” code and metadata.dll as before to run: public static void Main(string[] args) types private: local directory, not accessible by others  eg. Wolfram.NETLink shared: well-known location, can be GAC strong names: use crypto for signatures  then can add some versioning and trust

COM vs.NET Historically, COM provided this integration support for interfaces and interaction given a GUID, lookup the type library dynamically instantiate class do RPC to make calls in many cases Difficult to get right software engineering problems not type safe at all

ASP.NET and ADO.NET Use.NET languages in web pages thus can write typesafe code server-side or client-side Sharepoint interactions can log in Use the CLR to access databases in the manner of ODBC provides classes for access

Windows PowerShell New shell originally for MS Vista available for WinXP/2k3 native.NET instantiates arbitary.NET classes and accesses them Also can access COM objects Allows better interaction with programs Can it surpass bash and others?

First C# Program using System; namespace Test { int a = 137; class Hello { public static void Main(string[] args) { Console.WriteLine(“Hello {0}”, a); } } }

Constructions of Note using like import in Java: bring in namespaces namespace disambiguation of names like Internet hierarchical names and Java naming class like in Java single inheritance up to object

Constructions of Note Console.Write(Line) Takes a formatted string: “Composite Format” Indexed elements: e.g., {0} can be used multiple times only evaluated once {index [,alignment][:formatting]} also can use as in Java “Test “ + a

More C# : basic inheritance class A { protected int a; public virtual void print() { Console.WriteLine(“a = “ + a); } class B : A { public override void print() { Console.WriteLine(“a really = “ + (a + 137)); }