C/.NET

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C/.NET

• Jacob Lewallen

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C vs .NET

• .NET is a platform.
• Many languages compile to .NET
• VB.NET
• Python.NET
• Managed C
• C

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.NET

• Intermediate Language (IL) half-way
• Interpreted locally using JIT (Just-In-Time)
  compilers.
• Has a very nice standard library, comparable to
  Javas.
• Theme More open to its hosted system than
  Java.

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C Basics

• Garbage Collected
• Very Java-esque
• Main is static method in some class
• Designed for .NET, rather than adapted.
• Simple operator overloading
• Everything is an Object
• Java-like inheritance

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Safe vs Managed

• Unmanaged native code - non-IL code.
• Unsafe code code wrapped in Cs unsafe
  mechanism
• Relaxed type checking
• Pointers
• Flagged as unsafe and requires more trust.
• Unsafe code is still managed code.

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Syntax

• Think Java, if that fails think C
• public class ExampleApp
• public static void Main()
• string str Hello, World
• Console.WriteLine(str)

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Namespaces

• More like C namespaces, with some Java packages
  sprinkled in.
• using System.Collections
• Instead of using
• System.Collections.Hashtable
• Assemblies (DLLs) are named for the namespaces
  they contain, usually.

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Declaring a Namespace

• You can wrap your code in the namespace like so
• Namespace UCR.Technical.Seminar
• Nearly all code Ive ever seen has been wrapped
  in a Namespace.

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Collections

• System.Collections.Hashtable
• System.Collections.ArrayList
• Type-safe enumerations
• foreach (string name in users)
• .NET will do runtime type checking.

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Memory

• All allocated memory is garbage collected.
• We use new to create object instances.
• We can override a finalizer for our classes to
  handle cleanup.

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Value Types

• Categories Struct, Enumeration, Numeric Types
  (integers, floats, bools)
• Assignments create copies of the assigned value.
• Value types cannot contain null.
• int is an alias for System.Int32, all value types
  have an alias.

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Reference Types

• Also referred to as objects.
• Store references to actual data.
• Passed by reference, by default.

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Boxing

• Boxing - conversion from a value type to type
  object. Its implicit
• int x 23
• object o 23 object r x
• x is an integer on the heap, value is 23.
• o is an object, referencing a new value on the
  heap, thats 23.
• r is an object, referencing the value x.

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Unboxing

• Explicit conversion from a reference type, an
  object, to a value type.
• object o 23
• int x (int)o
• Type checking is done in the conversion.
• Can throw InvalidCastExceptions.

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Properties

• Replaces getter/setter paradigm.
• Wraps private member variables around more
  defined accessors.
• object.getName() you do object.Name.
• object.setName(Jacob) becomes object.Name
  Jacob
• Standard library uses upper case names for all
  properties.

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Properties

• Syntax for declaring a Property
• String Name
• get return (m_name)
• set m_name value
• Where m_name is our member variable.
• Read-only Properties have no set.

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Events/Delegates

• Calling/invoking methods w/o knowing anything
  about the methods object.
• Defining a Delegate
• public delegate void ButtonDelegate(string name)
• This delegate takes a string and returns nothing.

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Defining a Delegate

• Declare a variable for out delegate
• private ButtonDelegate m_presses
• We can create an instance of her
• m_presses new ButtonDelegate(SayHello)
• public bool SayHello(string name)
• Now, we can invoke/trigger the delegate
• m_presses(Hello, World)

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Using Delegates

• Delegates are used exclusively for event handling
  in .NET GUIs.
• Many design patterns (publisher/subscribe)

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Microsoft Whining

• You can download the .NET SDK from Microsoft.
  Youll get
• All the necessary command line utilities for
  developing with C.
• A few graphical tools for inspecting IL.
• Help via http//msdn.microsoft.com/
• Visual Studio is NOT required.

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Mono

• Open Source .NET/C implementation
• http//www.go-mono.com/

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Assembly

• Think shared-object - .dll or .so.

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ADO.NET
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System.XML