Net framework session02

Core Development with the Microsoft .NET Framework 2.0 Foundation

Objectives

In this session, you will learn to:
Describe the purpose of collections and collection interfaces
Implement the various classes available in the .NET
Framework 2.0
Implement generic list types, collections, dictionary types, and
linked-list types
Implement specialized string and named collection classes
Implement collection base classes and dictionary base types
Describe the purpose and creation of an assembly
Share an assembly by using the Global Assembly Cache
Install an assembly by using the Installer,
AssemblyInstaller, ComponentInstaller,
InstallerCollection, and InstallContext classes and
the InstallEventHandler delegate available in the .NET
Framework 2.0

Ver. 1.0 Slide 1 of 41


Examining Collections and Collection Interfaces

What are Collections?
• Collections are classes used to store arbitrary objects in an
organized manner.
• Types of collections available in .Net Framework are:
Arrays: Are available in the System.Array namespace and can
store any type of data.
Advanced Collections: Are found in the System.Collections
namespace and consist of the following collections:
Non-Generic Collections: With a non-generic collection, you could
store multiple types of objects in the collection simultaneously.
Generic Collections: When you create an instance of a generic
collection, you determine and specify the data type you want to store
in that collection.



Examining Collections and Collection Interfaces (Contd.)

What are Collection Interfaces?
• Collection interfaces specify all the necessary properties and
methods for an implementing class to provide the required
functionality and behavior of a collection.
• Every collection class, non-generic or generic, implements at
least one or more collection interfaces.



Working with Primary Collection Types

Create a Flexible Collection of Reference Types by Using
ArrayList class
• The ArrayList class is defined in the
System.Collections namespace.
• An ArrayList represents a list, which is similar to a single-
dimensional array that you can resize dynamically.
• The ArrayList does not provide type safety.

Dynamic Resizing



Working with Primary Collection Types (Contd.)

The following code snippet creates an ArrayList to store
names of countries:
ArrayList countries = new ArrayList();
countries.Add("Belgium");
countries.Add ("China");
countries.Add("France");
foreach (string country in countries)
{
Console.WriteLine (country);
}




Manage Collections by Using Stacks and Queues
• You can use Stacks and Queues to store elements when the
sequence of storing and retrieving them is an important issue.
• Stacks follow the last-in-first-out (LIFO) principle while Queues
follow the first-in-first-out (FIFO).

Queue FIFO

Stack LIFO




• The following code example shows the implementation of
the Stack class:
Stack s1 = new Stack();
s1.Push("1"); s1.Push("2"); s1.Push("3");
Console.WriteLine("topmost element: " +
s1.Peek());
Console.WriteLine("total elements: " +
s1.Count);
while (s1.Count > 0) { Console.Write(" " +
s1.Pop());
}
The output of the code example will be:
topmost element: 3
total elements: 3
321



the Queue class:
Queue q1 = new Queue();
q1.Enqueue("1");q1.Enqueue("2");q1.Enqueue("3");
Console.WriteLine("topmost element: " +
q1.Peek());
Console.WriteLine("total elements: " +
q1.Count);
while (q1.Count > 0) {
Console.Write(" " + q1.Dequeue());
}
The output of the code example will be:
topmost element: 1
total elements: 3
123



Enumerate the Elements of a Collection by Using an
Enumerator
• Iterators are sections of code that return an ordered sequence
of values of the same type.
• They allow you to create classes and treat those as
enumerable types and enumerable objects.




Access Reference Types Based on Key/Value Pairs and
Comparers
The Comparer class compares two objects to detect if they
are less than, greater than, or equal to one another.
The Hashtable class represents a collection of name/value
pairs that are organized on the basis of the hash code of the
key being specified.
The SortedList class represents a collection of name/value
pairs that are accessible either by key or by index, but sorted
only by keys.




the Comparer class:
string str1 = "visual studio .net";
string str2 = "VISUAL STUDIO .NET";
string str3 = "visual studio .net";
Console.WriteLine("str1 and str2 : " +
Comparer.Default.Compare(str1, str2));




The following code example creates a new instance of the
Hashtable class, named currency:
Hashtable currencies = new Hashtable();
currencies.Add("US", "Dollar");
currencies.Add("Japan", "Yen");
currencies.Add("France", "Euro");
Console.Write("US Currency: {0}",
currencies["US"]);




The following code example shows the implementation of
the SortedList class:
SortedList slColors = new SortedList();
slColors.Add("forecolor", "black");
slColors.Add("backcolor", "white");
slColors.Add("errorcolor", "red");
slColors.Add("infocolor", "blue");
foreach (DictionaryEntry de in slColors)
{
Console.WriteLine(de.Key + " = " + de.Value);
}




Store Boolean Values in a BitArray by Using the BitArray
Class
The BitArray class implements a bit structure, which
represents a collection of binary bits, 1s and 0s.
The Set and Get methods can be used to assign Boolean
values to a bit structure on the basis of the index of the
elements.
The SetAll is used to set the same value for all the
elements.



Just a minute

If you place a set of dinner plates, one on top of the
other, the topmost plate is the first one that you can
pick up and use. According to you, which class follows
the same principle?
Queue
BitArray
Stack
Hashtable

Answer
Stack



Working with Generic Collections

Create Type-Safe Collections by Using Generic List Types
The generic List class provides methods to search, sort, and
manipulate the elements of a generic list.
The generic List class can be used to create a list that
provides the behavior of an ArrayList.



Working with Generic Collections (Contd.)

The following code example shows the implementation of
the generic List:
List<string>names = new List<string>();
names.Add("Michael Patten");
names.Add("Simon Pearson");
names.Add("David Pelton");
names.Add("Thomas Andersen");
foreach (string str in names)
{
Console.WriteLine(str);
}




Create Type-Safe Collections by Using Generic Collections
The generic Stack class functions similarly to the non-generic
Stack class except that a generic Stack class contains
elements of a specific data type.
The generic Queue class is identical to the non-generic Queue
class except that the generic Queue class contains elements of
a specific data type.
The generic Queue class is used for FIFO applications.
The generic Stack class is used for LIFO applications.




Access Reference Types Based on Type-Safe Key/Value
Pairs
• In generic key/value pairs, the key is defined as one data type
and the value is declared as another data type.
• The following classes can be used to add name and value
pairs to a collection:
Dictionary: Represents in the value the actual object stored,
while the key is a means to identify a particular object.
SortedList: Refers to a collection of unique key/value pairs
sorted by a key.
SortedDictionary: Uses a faster search algorithm than a
SortedList, but more memory.




Create Type-Safe Doubly Linked Lists by Using Generic
Collections
With the generic LinkedList class, you can define nodes
that have a common data type with each node pointing to the
previous and following nodes.
With a strongly typed doubly linked list you can traverse
forward and backward through the nodes to reach a particular
node.

Doubly LinkedList



Just a minute

What is a doubly linked list?

Answer
A collection in which each node points to the previous and
following nodes is referred to as a doubly linked list.



Working with Specialized Collections

What Are Specialized Collections?
Specialized collections are predefined collections that serve a
special or highly specific purpose.
These collections exist in the
System.Collections.Specialized namespace
The various specialized collections available in .Net
Framework are:
String classes
Dictionary classes
Named collection classes
Bit structures



Just a minute

What is a specialized string collection?

Answer
A specialized string collection provides several string-specific
functions to create type-safe strings.



Working with Collection Base Classes

Create Custom Collections by Using Collection Base
Classes
Collection base classes provide the abstract base class for
strongly typed non-generic collections.
The read-only version of the CollectionBase class is the
ReadOnlyCollectionBase class.



Working with Collection Base Classes (Contd.)

Create Custom Dictionary Types by Using Dictionary Base
Types
Dictionary base types provide the most convenient way to
implement a custom dictionary type.
Custom dictionary types can be created by using:
DictionaryBase class
DictionaryEntry structure



Just a minute

Categorize the following features into CollectionBase
class and the DictionaryBase type?
Helps create custom collections
Helps create a custom dictionary
Provides the public member Count
Is a base collection of key value/pairs

Answer
Collection Base class Dictionary Base type
Helps create custom collections Helps create a custom dictionary
Provides the public member Count Is a base collection of key value/pairs



Working With An Assembly

What Is an Assembly?
• An assembly is a self-contained unit of code that contains all
the security, versioning, and dependency information.
• Assemblies have several benefits like:
Resolve conflicts arising due to versioning issues.
Can be ported to run on multiple operating systems.
Are self-dependant.



Working With An Assembly (Contd.)

Create an Assembly
• You can create the following two types of Assemblies.
• Single-file assemblies: are self-contained assemblies.
• Multifile assemblies: store different elements of an assembly in
different files.
• You can create an assembly either at the command prompt by
using command-line compilers or by using an IDE such as
Visual Studio .NET 2005.
Types of Assemblies

Single-file Multifile




To create an assembly with the .exe extension at the
command prompt, use the following syntax:
compiler command module name
For example, if you want to compile a code module
called myCode into an assembly you can type the
following command:
csc myCode.cs




The three most common forms of assemblies are:
.dll : A .dll file is an in-process executable file. This file cannot
be run independently and is called by other executable files.
.exe: An .exe file is an out-of-process executable file that you
can run independently. An .exe file can contain references to
the .dll files that get loaded at run time.
.netmodule: A .netmodule is a block of code for compilation. It
contains only the type metadata and the MSIL code.



Sharing an Assembly by Using the Global Assembly Cache

What is Global Assembly Cache?
• The global assembly cache is a system-wide code cache
managed by the common language runtime.
• Any assembly that needs to be shared among other
applications is typically installed in the global assembly cache.
• On the basis of sharing, assemblies can be categorized into
two types, private assemblies and shared assemblies.



Sharing an Assembly by Using the Global Assembly Cache (Contd.)

Creating and Assigning a Strong Name to an Assembly
• A strong name provides a unique identity to an assembly.
• For installing an assembly in the global assembly cache, you
must assign a strong name to it.
• You can use Sn.exe provided by the .NET Framework to
create and assign a strong name to an assembly.
• For creating a strong name for an assembly you can open the
Visual Studio 2005 Command Prompt and type the following
command:
• SN -k KeyPairs.snk
SN is the command to generate the strong key and
Keypairs.snk is the filename where you are storing this key.



Sharing an Assembly by Using the Global Assembly Cache (Contd.)

Deploy an Assembly into the Global Assembly Cache
• Deploying an assembly in the global assembly cache is
necessary when you need to share the assembly with other
applications.
• There are three methods to deploy an assembly into the global
assembly cache:
• Windows Explorer
• Gacutil.exe
• Installers
• The syntax to use Gacutil.exe is gacutil –i/assembly name. The
-i option is used to install the assembly into the global
assembly cache.



Installing an Assembly by Using Installation Types

What are Assembly Installers?
• Assembly installers are used to automate the process of
installing assemblies.
• You can create installers either by using:
Visual Studio: Allows you to create four types of installers:
• Setup project
• Web Setup project
• Merge Module project
• CAB project
• Command Prompt: Enables more flexibility in customizing your
assembly installers.



Installing an Assembly by Using Installation Types (Contd.)

Create Custom Installation Applications by Using the
Installer Class
• The .NET Framework provides the Installer class as a base
class to create custom installer classes.
• To create a custom installer class in your setup code, perform
the following steps:
Create a class that is inherited from the Installer class.
Implement overrides for the Install, Commit, Rollback, and
Uninstall methods.
Add RunInstallerAttribute to the derived class and set it to
true.
Invoke the installer.




Install an Assembly by Using the AssemblyInstaller
Class
You can use the AssemblyInstaller class to load an
assembly and run all its installer classes.
The AssemblyInstaller class belongs to the
System.Configuration.Install namespace.




Copy Component Settings for Runtime Installation
ComponentInstaller class that has the ability to let custom
installer classes to access information from other running
components during the installation process.
The installer can access the required information from another
component by calling the CopyFromComponent method of the
ComponentInstaller class.

Custom Installer Running Components
Classes




Manage Assembly Installation by Using Installer
Classes
• The .NET Framework provides the following Installer
classes:
InstallerCollection: Provides methods and properties that
the application will require to manage a collection of Installer
objects.
InstallContext: Maintains the context of the installation in
progress.




Handle Installation Events by Using the
InstallEventHandler Delegate
• InstallEventHandler delegate can be used to run custom
actions at certain points during the installation process.
• The various events that can be handled during installation are:
BeforeInstall
AfterInstall
Committing
Committed
BeforeRollback
AfterRollback
BeforeUninstall
AfterUninstall



Summary

In this session, you learned that:
Collections are classes in which you store a set of arbitrary
objects in a structured manner.
Collection interfaces specify all the necessary properties and
methods for an implementing class to provide the required
functionality and behavior of a collection.
Primary or non-generic collection types can be dynamically
resized, but do not provide type safety.
Stack and Queue classes are helpful for storing a set of
objects in a collection where the sequence of adding objects is
important.
Type-safe doubly linked lists can be created by using generic
collections.
Specialized collections are predefined collections that serve a
special or highly specific purpose.



Summary (Contd.)

Collection base classes provide the abstract base class for
strongly typed non-generic collections.
An assembly is a collection of types and resources that are
built to work together and form a logical unit of functionality.
The global assembly cache is a system-wide code cache
managed by the Common Language Runtime (CLR).
An assembly that is installed in the global assembly cache to
be used by different applications is known as a shared
assembly.
Assembly installer is a utility that help automate installation and
uninstallation activities and processes.


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