overview of the microsoft.net framework jim fiddelke, greenbrier & russel

Overview of the Overview of the Microsoft .NET FrameworkMicrosoft .NET Framework

Jim Fiddelke, Greenbrier & Russel

AgendaAgenda

• Overview• The CLR• The Framework Class Library• ASP.NET• Web Forms• Web Services• Data Access• WinForms• Questions and Answers

OverviewOverview

What is .NETWhat is .NET

• Three main elements:– The Framework (CLR, FCL, ASP, WinForms)– The Products (Windows, Visual Studio, Office)– The Services (My Services)

• Development began in 1998.• Framework Goals:

– Improved reliability and integrated security.– Simplified development and deployment.– Unified API, multi-language support.

• New version of COM?• XML is the .NET “Meta-Language”.• All MS server products eventually .NET-enabled.

The .NET FrameworkThe .NET Framework

Windows FormsWindows FormsWindows FormsWindows FormsASP.NETASP.NETASP.NETASP.NET

Web Services

ASP.NET Application Services

Web Forms ControlsControls Drawing

Windows Application Services

Framework Class LibraryFramework Class LibraryFramework Class LibraryFramework Class Library

ADO.NET

Network

XML

Security

Threading

Diagnostics

IO

Etc.

Common Language RuntimeCommon Language RuntimeCommon Language RuntimeCommon Language Runtime

Memory Management Common Type System Lifecycle Monitoring

The .NET FrameworkThe .NET Framework

• Beta 1 released Oct, 2000.• Beta 2 released July, 2001.• Finalized in Dec, shipping in Feb 2002.• SDK and Visual Studio.NET (includes SDK) run on

Windows NT 4.0, 2000, and XP.• Redistribution Pack (runtime) runs on Windows 98, NT

4.0, 2000, ME, and XP.• Framework will ship with Windows .NET Server (mid-

2002) and beyond.

The New Languages - C# and VB.NETThe New Languages - C# and VB.NET

• Performance differences very minor.• VB.NET introduces long sought-after features:

– Inheritance– Parameterized Class Constructors– Function Overloading– Multi-Threading– Structured Error Handling– Creating NT Services

• VB.NET not backward compatible with VB6.• VB6 will be supported until the third release of VB.NET

(5-6 years away).• C#

– New modern, object-oriented language– Similar to C++/Java– “High-Fidelity” language of .NET

What About Java?What About Java?

• Microsoft is developing “JUMP” (Java User Migration Path to .NET). A set of conversion tools.

• Late-Breaking News: Visual Studio.NET will include a Java component called Visual Java.NET (or maybe Visual J# .NET).

.NET vs. J2EE.NET vs. J2EE

• Both are similar in many ways:– Server- and client-side model for building enterprise

applications.– Virtual machine designed to inspect, load, and execute

programs in a controlled environment.– APIs for creating both fat- and thin-client models.– APIs for foundation services (data access, directory,

remote object calls, sockets, forms).– Development environment for dynamic web pages.

• J2EE: “Language-Dependent & Platform-Independent”.• .NET: “Language-Independent & Platform Dependent”.

J2EE: Language-Specific, Platform- J2EE: Language-Specific, Platform- IndependentIndependent

Person.java

Address.java

Company.java

Java VMPersonbytecodes

CompanybytecodesAddress

bytecodes

LinuxLinux

WindowsWindows

SolarisSolaris

Java VM

Java VM

Java VM

Deploy

.NET: Language-Independent, Platform- .NET: Language-Independent, Platform- SpecificSpecific

Person.vb

Address.cs

Company.cbl

CLRPersonMSIL

CompanyMSILAddress

MSIL

WindowsWindows

WindowsWindows

WindowsWindows

CLR

CLR

CLR

Deploy

(Visual Basic)

(C#)

(Cobol)

J2EEJ2EE

• The core (JVM and standard class libraries) are mature.• 2 million Java programmers.• J2EE implementations are not entirely cross-platform.• Java’s true potential is realized only when all (or most)

development is done in Java.• Changing the Java language specification has an

enormous impact on the entire platform.

.NET.NET

• Being newer, .NET adds improvements such as native XML support.

• 6 million VB developers.• All development and deployment is Windows.

The CLRThe CLR

What is the CLRWhat is the CLR

• The CLR is at the core of the .NET platform - the execution engine.

• A “Managed Execution Environment”. Manages the execution of code and provides services that make development easier.

• Code developed for a compiler that targets this platform is referred to as “Managed Code”.

• Code that relies on COM and the Win32 API is “Un-Managed Code”.

• VB6 is 100% “Un-Managed”, VB.NET is 100% “Managed”.

Key Features and BenefitsKey Features and Benefits

• Cross-Language Integration• Cross-Language Inheritance• Cross-Language Exception Handling• Enhanced Security• Versioning and Deployment Support• Debugging and Profiling Services• Automatic Memory Allocation and Management• A Common Type System• Object Lifecycle Monitoring and Garbage Collection


• Key objective is to handle much of the “programming infrastructure”, such as memory management and object proxies. Much is replaced by metadata.

• Memory management is self-configuring and self-tuning.• Many common bugs should be eliminated (such as

memory leaks).• Tool support - designed to work well with designers,

wizards, debuggers, etc.• CLR replaces the existing runtime layers of COM, MTS,

COM+.


• Language interoperability is built into the Framework by means of a Common Type system.

• There is a CLR-to-COM interoperability layer.• Better debuggers - can jump between source across

different languages.• Simplified deployment - no more “DLL Hell”. CLR

supports “side-by-side” execution - the ability to load and execute multiple versions of the same assembly.


COM provides a way for components to integrate. However, each component must provide the “plumbing” and objects cannot directly interact.


With the .NET CLR, components are built on a common substrate. No “plumbing” is needed and objects can directly interact.

CLRCLR

Application TypesApplication Types

• The CLR supports the following types of applications:– Console– Windows Forms– Web Forms– Web Services– Service Control Manager Services (NT Services)– Tools and Utilities– Components

The Common Language SpecificationThe Common Language Specification

• CLR works with multiple languages - including those developed by third parties (approx. 22).

• Each language compiler may support different subsets of the runtime’s functionality.

• The Common Language Specification (CLS) defines the requirements for a .NET component to be completely usable by other .NET applications.

• The CLS spec. defines a subset of the CLR types and features.

• The Framework Class Library (FCL) itself is fully-compliant with the CLS.

• VB.NET is fully CLS compliant.• C# is not - you can create C# components that expose

types not usable by VB.NET.• There is a compiler directive to force CLS-compliance.

MSIL and JIT CompilationMSIL and JIT Compilation

• Source code is compiled into MSIL (Microsoft Intermediate Language). Similar to Java bytecodes - CPU-independent instructions.

• MSIL allows for runtime type-safety and security, as well as portable execution platforms (all Windows). MSIL code cannot play tricks with pointers or illegal type conversions.

• The MSIL architecture results in apps that run in one address space - thus much less OS overhead.

• Compilers also produce “metadata”:– Definitions of each type in your code.– Signatures of each type’s members.– Members that your code references.– Other runtime data for the CLR.

MSIL and JIT CompilationMSIL and JIT Compilation

• Metadata in the load file along with the MSIL enables code to be self-describing - no need for separate type libraries, IDL, or registry entries.

• When code is executed by the CLR, a JIT compilation step occurs. Code is compiled method-by-method to native machine code.

Garbage CollectionGarbage Collection

• COM manages object lifetimes through reference counting. Circular references were a big problem.

• CLR manages objects through a process of garbage collection. CLR will detect and break down circular references.

• COM has “deterministic finalization” - you know that when you release the last reference to an object, that object goes away, and can code accordingly.

• CLR has “non-deterministic finalization”.

MetadataMetadata

• Metadata is generated by the compiler and stored in the executable (EXE or DLL).

• Similar to a COM type library - contains information that describes the component’s public types (enums, structures, interfaces, and classes).

• IDL no longer used.• No need to define an interface to program against a

class.• Interface-based programming still alive and well in .NET.• Metadata includes:

– Assembly - name, version, culture, public key, exported types, security permissions.

– Base classes and interfaces.

Packaging: Modules, Types, Assemblies, Packaging: Modules, Types, Assemblies, and the Manifestand the Manifest

• A “module” refers to a managed binary, such as an EXE or DLL.

• Modules contain definitions of managed types, such as classes, interfaces, structures, and enumerations.

• An assembly can be defined as one or more modules that make up a unit of functionality. Assemblies also can “contain” other files that make up an application, such as bitmaps and resource files.

• An assembly is not a physical file.• An assembly is the the fundamental unit of deployment,

version control, activation scoping, and security permissions.


• An assembly is a set of boundaries:– A security boundary - the unit to which permissions are

requested and granted.– A type boundary - the scope of an assembly uniquely

qualifies the types contained within.– A reference scope boundary - specifies the types that are

exposed outside the assembly.– A version boundary - all types in an assembly are

versioned together as a unit.


• An assembly contains a “manifest”, which is a catalog of component metadata containing:– Assembly name.– Version (major, minor, revision, build).– Assembly file list - all files “contained” in the assembly.– Type references - mapping the managed types included in

the assembly with the files that contain them.– Scope - private or shared.– Referenced assemblies.

• In many cases, an assembly consists of a single EXE or DLL - containing the module’s MSIL, the component metadata, and the assembly manifest. In other cases, the assembly may consist of many DLLs, with the manifest in it’s own file.

• No MSIL code can ever be executed unless there is a manifest associated with it.


• Two types of assemblies:– Private - Usually deployed in the same directory as the

client application and used only by a single application.– Shared - Used by any application and usually installed in a

special Global Assembly Cache.

• Version information from a dependent assembly is recorded in a client manifest.


AssemblyAssemblyAssemblyAssembly

ManifestManifest

ModuleModule

MetadataMetadata

MSILMSIL

TypeType TypeTypeTypeType

The Common Type SystemThe Common Type System

• At the core of the Framework is a universal type system called the .NET Common Type System (CTS).

• Everything is an object - but efficient.• It is this CTS that make cross-language inheritance

possible.• All types fall into two categories - Value types and

Reference types.• Value types contain actual data (cannot be null). Stored

on the stack. Always initialized.• Three kinds of value types: Primitives, structures, and

enumerations.• Language compilers map keywords to the primitive

types. For example, a C# “long” is mapped to System.Int32.


• Reference types are type-safe object pointers. Allocated in the “managed heap”.

• Four kinds of reference types: Classes, arrays, delegates, and interfaces.

• When instances of value types go out of scope, they are instantly destroyed and memory is reclaimed.

• When instances of reference types go out of scope, they are garbage collected.

• Boxing = converting an instance of a value type to a reference type. Usually done implicitly through parameter passing or variable assignments.

• UnBoxing = casting a reference type back into a value type variable.


Primitive TypesPrimitive Types

Int16

Int32

Int64

Single

Double

Decimal

Boolean

Byte

Char

Currency

DateTime

TimeSpan

ObjectObject

ArrayArrayStringString

EnumEnum

ValueTypeValueType ExceptionException DelegateDelegate

Multicast

Delegate

Multicast

Delegate

Class1Class1

Class2Class2

Class3Class3

AttributesAttributes

• Attributes in the CLR allow you to add additional information to the classes you create. This information is read by using the System.Reflection classes defined in the Framework Class Library.

• One particular example of using attributes is the “[WebMethod]” attribute used to expose a Web Service method.

Error HandlingError Handling

• Error handling in the CLR is structured and consistent.• Uses the “Try…Catch…Finally” pattern.• “Throw” enables you to raise an exception.

DelegatesDelegates

• A new concept that is central to the programming model of the CLR.

• Delegates are like function pointers, but are actually type-safe, secure, managed CLR objects.

• The CLR guarantees that a delegate points to a valid method.

• You get the benefits of function pointers without the dangers.

• Each delegate is based on a single method signature.• Commonly used for callbacks.• Delegates are basis of event handlers.

DeploymentDeployment

• The CLR does not require registry entries for assemblies or managed types.

• Assemblies can be deployed using the Windows Installer, Internet Explorer, or XCOPY.

• Apps can be run from a CD with no installation at all.• Side-by-side deployment means you can create new

versions of an assembly without having to maintain backwards compatibility with previous versions.

• Both versions of the same assembly can run together (in the same address space on the same machine) - supporting both old and new clients.

The Bigger Picture?The Bigger Picture?

• The CLS and CTS are actually a part of a bigger specification called the CLI (Common Language Infrastructure).

• The CLI and C# have been submitted to the ECMA for standardization.

• MSIL and the CLR are simply Microsoft implementations of the CLI for Windows.

• Open-Source organizations are developing .NET ports for other operating systems.

• MS is helping Corel with a .NET port to FreeBSD.• The Free Software Foundation and Ximian are working

on a .NET port to Linux.

The Framework Class LibraryThe Framework Class Library

What is the Framework Class LibraryWhat is the Framework Class Library

• The FCL is a hierarchical class library that can be utilized across multiple languages (CLS) and platforms (Windows).

• Enables consistent programmatic access to the .NET runtime environment.

• Integrates the functionality from existing COM and other runtime libraries.

• Windows API, Data Access, XML, etc. all accessible in a consistent, simplified, unified way.

What is the Framework Class LibraryWhat is the Framework Class Library

• Contains thousands of reusable classes, interfaces, and components that can be used for:– Accessing the file system, text files, and databases.– Working with XML.– Developing components and Web Services.– Managing application configurations.– Working with Directory Services, Event Logs, Processes,

Message Queues, and Timers.– Handling images and strings.– Creating and managing threads.– Accessing assembly metadata and managing the CLR.– Developing Windows Forms applications.– Developing Web Forms applications.– Managing application security.


• Cross-Language Interoperability• Consistent and Unified Programming Model• Object-Oriented and Extensible Class Library

NamespacesNamespaces

• A Namespace is a user-defined scope in which managed types are defined.

• The FCL is organized into 98 namespaces.• FCL namespaces are organized in a hierarchy. The

System namespace is at the topmost level, and almost all other namespaces are subordinate.

COM InterOpCOM InterOp

• “Classic COM” components can be used in a .NET application, and vice-versa.

• ASP.NET and VB.NET still support CreateObject().• C# can call COM servers via the InteropServices and

Reflection routines.• Interop layer automatically converts errors (HRESULTS)

into ComException exceptions.• The Type Library Importer utility takes a standard COM

type library and creates an assembly containing the equivalent .NET metadata. The resulting DLL is essentially a mananged-code face on the COM component.

• Best practice is to recompile the components.

ASP.NETASP.NET


• Better Performance.– Script code replaced by the .NET languages.– Code is JIT compiled (or pre-compiled).– Early binding, strong typing, better error handling.

• Better Programming Models.– ASP.NET part of the FCL.– All ASP code consists of subclassed framework classes.

• Less Coding.– Control state is built-in.– More data-bound controls.

• Easier to use Components.– DLLs can be replaced in the procedure cache without

stopping the site.– No more COM/MTS registration issues.

• Extensive Caching Features.

ConfigurationConfiguration

• All configuration is done via an XML file - Web.config.• Web.config files are stored in the same virtual directory

tree as the rest of the application files.• Can be changed on the fly, or redeployed using XCOPY,

without stopping the site.• A Web.config can exist for each application. Config files

inherit settings from parent config files.• Additional sections and elements can be added for

application-specific settings.

Global.asaxGlobal.asax

• Replaces (and is completely compatible with) the Global.asa file.

• Provides for application-wide event handlers and other global logic for the web application. Applies to both the Web Forms and Web Services programming models.

• Can contain the following:– Application Directives.– Code Declaration Blocks.– Server-side Object Tags.– Server-side Include Directives.

Session State ManagementSession State Management

• All session state is (by default) stored externally from the “worker” processes in dedicated “.NET State Server” processes running as separate NT processes.

• No end-user code, and no live object references reside in these processes.

• This process isolation improves ASP.NET’s reliability.• State Server can be a separate machine available to all

web servers in a web farm.• Session Id strings are 120-bit keys. Passed between

page requests via either an HTTP cookie or a “munged URL”.

• “State Blobs” can be stored in SQL Server database.

Web FormsWeb Forms

What are Web FormsWhat are Web Forms

• Web Forms are a new control-based, event-driven execution model for web user interfaces.

• Features a “drag-and-drop” designer (Visual Studio 7), more cleanly-encapsulated functionality, and less coding compared to ASP.

• Web Forms are pages with “.aspx” extensions and processed by XSPIAPI.DLL. ASP pages still processed by ASP.DLL. Thus old and new ASP apps can run side-by-side in IIS.

• An ASP.NET page is a class. Inherits from System.Web.UI.Page. Constructed and compiled on first reference, then stored in the procedure cache.


• Stronger separation of content (HTML) and code.• Designed to work on any browser.• Easier debugging with a trace facility.• Page state management handled for you.• Event-based programming model is cleaner to code.• Coding can be done in any CLR language.• Much better performance than ASP.

Coding StructureCoding Structure

• Directives appear at the start of the .aspx file.• Code Declaration Blocks are blocks of code contained in

special <SCRIPT> tags.• Code Rendering Blocks are code delimited by the

familiar <%…%> tags.• Code in declaration blocks can alternatively be placed in

an external source file, using the Inherits and Src directives. This is called “code-behind”.

• External page code can be pre-compiled. Omit the Src directive and place the DLL in the \bin directory.

Event-Based Programming ModelEvent-Based Programming Model

• Existing ASP code has little structure.• ASP.NET uses an event-based model. Events are

defined for the Page class, which you provide code for.• Various events are fired, on the server, by the controls.• A “post-back” occurs as a result of a UI event, such as a

button click.• The state of the page’s controls are maintained

automatically via a hidden form field.

Page LifecyclePage Lifecycle

• ASP.NET Web Form pages go through a series of processing stages at which points you can connect event-handler code.

• Some commonly-used phases:– Configuration (Page_Load). Page and control view state

are restored (or initialized). You can check the IsPostBack property.

– Event Handling. Many controls will trigger a postback and their corresponding events are fired. Other controls may not trigger the postback, but their relevant events still fire on the server when the postback occurs.

– Cleanup (Page_UnLoad). The page has finished rendering.

Server ControlsServer Controls

• Server controls are HTML elements contained in a FORM that remember their state between page requests, and generate events which are processed on the server.

• In some cases, they use new tag names that are recognized by ASP.NET but are substituted with standard HTML tags for the browser. For example, <asp:ListBox> is substituted with <SELECT>.

• Fall into two broad categories: HTML Controls and Web Controls.

HTML ControlsHTML Controls

• Defined in the System.Web.UI.HtmlControls namespace.• Server-side references to some of the most commonly-

used standard HTML elements.• Object model for these controls maps very closely to the

corresponding HTML element.• Declared using the standard HTML tags, but with the

addition of the “runat=server” attribute.• Example:

– <BUTTON OnServerClick=“Button_Click” RunAt=“Server”>

Web ControlsWeb Controls

• Defined in the System.Web.UI.WebControls namespace.• These are enhanced server-side controls, and do not

necessarily map one-to-one with HTML elements• Declared using XML tags such as <asp:Button>.• Are rendered to the browser based on the browser’s

capabilities and other factors. For example, the <asp:Button> control may render as an <INPUT type=submit> or as a <BUTTON>.

• Can be grouped into five categories:– Intrinsic controls, such as the ASP:RadioButton.– Rich controls, such as the ASP:Calendar.– List controls, such as ASP:DataGrid.– Validation controls, such as ASP:RangeValidator.– Mobile controls for encapsulating WML for WAP requests

(post beta 1).

Validation ControlsValidation Controls

• Used to validate the contents of other controls.• Rendered as client-side script if the browser supports it,

else server-side.• Server-side validation can be forced by setting the

EnableClientScript property to false.• Validation controls are:

– ASP:RequiredFieldValidator– ASP:RangeValidator– ASP:CompareValidator– ASP:RegularExpressionValidator– ASP:CustomValidator– ASP:ValidationSummary

User ControlsUser Controls

• User Controls are formed by encapsulating other ASP.NET server controls into a composite control.

• Great way of extending ASP.NET, promoting reuse of server-side code, and is more object-oriented than using include files.

• Controls created in this fashion are identified by a namespace, avoiding name collisions.

Web ServicesWeb Services

What are Web ServicesWhat are Web Services

• “Software as a Service”.• Internet communication is abstracted.• Programmable components that provide business logic

to web or desktop applications using XML for message formatting and the standard Internet protocols (HTTP, SSL, etc.) for communications (SOAP).

• Not a new concept - and .NET is not required to build SOAP servers or clients. The MS vision is simply that .NET becomes the easiest way (thus most popular).

• MS doesn’t own the standards.• Part of the .NET initiative is “My Services” (formerly

known as “Hailstorm”), which are a set of Microsoft .NET Foundation Web Services. The first example of this is Passport. Another good example is Microsoft’s TerraServer.

Why Use Web ServicesWhy Use Web Services

• No physical distribution of software. Less cost, easier maintenance.

• Easier to implement than DCOM, Sun’s RMI, CORBA. Web Services do not rely on any proprietary standards or platform.

• Designed with a loose-coupling between the service provider and the service consumer. One can run without the other.

• XML is the defacto standard for data interoperability.

Web Service Wire FormatsWeb Service Wire Formats

• Web Services use the standard Internet communication protocols. This enables basic communication between providers and consumers, regardless of platform.

• This is SOAP (Simple Object Access Protocol).• SOAP is a messaging protocol that uses XML for

formatting service requests and replies.• SOAP defines an envelope formatting and processing

mechanism for complex message structures and allows for loose coupling.

Web Service DescriptionWeb Service Description

• A Web Service Description defines all the supported methods that a Web Service provides.

• This is WSDL (Web Service Description Language).• WSDL is an XML grammar that developers and

development tools use to represent the capabilities and syntax of a Web Service.

• The .NET Framework has utilities for dealing with WSDL, such as Wsdl.exe.

Web Service DiscoveryWeb Service Discovery

• This is the aspect of making the presence and capabilities of a Web Service known to the world.

• This is the UDDI (Universal Discovery, Description, and Integration) business registry service.

• Initiated by Ariba, IBM, and Microsoft. Supported by more than 130 companies.

• Provides a standard place to register Web Services. Check out www.uddi.org.

• UDDI is a specification built on SOAP/XML and defines a document format and protocol for searching and retrieving discovery documents - which in turn link to DISCO documents.

• DISCO (Discovery of Web Services) is a Microsoft protocol for retrieving the contracts for Web Services (WDSL documents).

• Incredibly easy using the .NET Framework. Start by opening a new Visual Studio “Web Service” project, or simply code from scratch in Notepad.

• Like Web Forms, Web Services are part of ASP.NET. You create your Web Service as an .asmx file with the following directive:– <%@ WebService Language=“C#” Class=“MyClass” %>

• Code can be in any .NET language. Code can be in the .asmx file or in a separate module.

• Your class always inherits from System.Web.Services.WebService.

• To expose a method, you use the [WebMethod] attribute and make the method public.

Building a Web ServiceBuilding a Web Service

Calling a Web Service via HTTP GetCalling a Web Service via HTTP Get

• By requesting a Web Service URL from the IE Address field, ASP.NET will respond with a neatly-formatted page that describes the Web Service and it’s methods. This page even provides a simple means to run the methods.

• This is not UDDI or DISCO. Just a nicely-formatted page built from the metadata.

• You can get the WSDL by appending “?wsdl” to the URL.• To call a method, append the method name and

parameters to the URL like this:– /MethodName?Parm=Value&NextParm=NextValue…

• Calling the service in this manner will result in a simple XML response containing the return value.

Calling a Web Service via HTTP PostCalling a Web Service via HTTP Post

• The WSDL describes the requirements for doing this.• The Web Service expects that the incoming parameter

values be contained in FORM fields with specific names. Therefore, your FORM has to contain INPUT elements named according to the WSDL. The ACTION attribute names the method:– <FORM Method=“Post”

Action=“StockTicker.asmx/GetStockPrice”>

• The response is an XML string.

Calling a Web Service via SOAPCalling a Web Service via SOAP

• Using SOAP is the most comprehensive manner to invoke a Web Service, but can be complicated.

• Fortunately, the .NET Framework provides utilities to make this easier.

• You build a “proxy” class which is a mirror image of the Web Service. It is run locally on your system, and appears to your application as the Web Service.

• The proxy handles the SOAP communications with the actual Web Service.

• You generate the proxy class using the “Web Services Description Language” tool (wsdl.exe).

• Note that Visual Studio will do this for you simply by adding a “Web Reference” to your project.

Data AccessData Access

ADO.NETADO.NET

• ADO.NET is the primary library for building database solutions within the .NET Framework.

• ADO.NET does not replace ADO. ADO and OLEDB are still the preferred means for building COM applications.

• ADO.NET specifically designed to build highly-scalable applications using a 3-tiered, connectionless model.

• Better support for “offline” applications.• Most of the time in ADO.NET you are working with

objects that have no active database connection.• ADO.NET is based on XML.

ADO.NETADO.NET

• The ADO.NET objects are implemented in the following namespaces:– System.Data - Base ADO.NET objects and types.– System.Data.Common - Classes shared by the .NET data

providers.– System.Data.OleDb - OLEDB .NET data provider.– System.Data.SqlClient - SQL Server .NET data provider.– System.Data.SqlTypes - Native SQL Server data types.

• System.Data.OleDb and System.Data.SqlClient contain roughly the same classes.

• System.Data.OleDb is for using OLEDB data sources, like ADO is used for now.

• System.Data.SqlClient is specifically for SQL Server, and is highly optimized for performance.

ADO.NET ArchitectureADO.NET Architecture

.NET Data Provider.NET Data Provider.NET Data Provider.NET Data Provider

Connection

Transaction

Command

Parameters

DataReader

DataAdapter

SelectCommand

InsertCommand

UpdateCommand

DeleteCommand

DatabaseDatabase

DataSetDataSetDataSetDataSet

DataTableCollection

DataTable

DataRowCollection

DataColumnCollection

ConstraintCollection

DataRelationCollection

XMLXML

OleDbConnection / SqlConnectionOleDbConnection / SqlConnection

• These classes represent an open connection to a data source.

• Provide the same service as the ADO Connection object.• Feature the familiar properties (ConnectionString, etc.)

and methods (Open, BeginTransaction, Close, etc.).

OleDbCommand / SqlCommandOleDbCommand / SqlCommand

• These classes represent a query command to be made against a data source.

• Mirrors the ADO Command object with one very big difference: Data that is returned from SELECT statements is obtained via an OleDbDataReader or SqlDataReader, which is always a forward-only, read-only stream.

OleDbDataReader / SqlDataReaderOleDbDataReader / SqlDataReader

• Uses streaming methods, such as Read() to fetch data rows.

• Very fast, efficient object for read-only scenarios.

OleDbDataAdapter / SqlDataAdapterOleDbDataAdapter / SqlDataAdapter

• Represent a set of data commands and a database connection which are used to fill a DataSet and update the corresponding database.

• These objects are used for stateless batch update scenarios.

• Select, Insert, Update, and Delete commands are grouped together in one composite object.

• Used to interface a database with a DataSet object.

The DataSetThe DataSet

• The ADO.NET DataSet object can be described as an in-memory database.

• A DataSet object can contain a hierarchy of objects that represent tables, relationships, columns, rows, and constraints.

• It is not tied to any database product.• The child objects can be manipulated in many ways.

Not only can the data be updated, but additional child objects (tables, relationships, rows, etc.) can be created.

• The DataSet has been designed as the connectionless workhorse for the framework, servicing the need to bridge the Business Logic and Data Access layers in a multi-tiered implementation.

WinFormsWinForms

What are WinFormsWhat are WinForms

• The new way to produce standard Windows desktop applications.

• Based on the Windows Foundation Class (WFC) produced for Visual J++.

• All WinForm applications that you create are done by subclassing the .NET base classes.

• Can be written in any .NET language.• Visual Studio 7 supplies designers for RAD.• Merges the drag-and-drop RAD spirit of VB with the

inheritance/reuse/power of MFC.


• Like any other .NET application, WinForm applications can be deployed with a simple XCOPY. No registration of controls, etc.

• Full integration with the .NET Framework. You have all the features of the FCL available for your desktop applications, including Web Services.

• Visual Inheritance. WinForms are .NET classes. Like any other CLR managed type, your classes can inherit from other classes.

• Can still use ActiveX controls.

The FrameworkThe Framework

• WinForms begin at the System.WinForms namespace.• This namespace contains the Form class and many

controls that can be added to forms to create user interfaces.

• System.WinForms contains the Application class, with a static method called Run. This displays a form and provides the message pump.

• The Form class is the base class for all forms you create.

Questions and AnswersQuestions and Answers

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overview of the microsoft.net framework jim fiddelke, greenbrier & russel

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