1. Jim Fawcett CSE687 – Object Oriented Design Spring 2001
Microsoft .Net
Jim Fawcett
CSE687 – Object Oriented Design
Spring 2001

2. Potential of the Web
The web started as an extended library of relatively static web pages ( ).
Web commercialization added a market place of products, e.g., Amazon.com, Dell.com, … ( ).
What’s next?

3. Semantic Web W3C’s Director, Tim-Berners-Lee sees a “Semantic Web”.
Web pages with semantic tags and catalogs of definitions and relationships between tags that convey “meaning” to computers.
The idea is to develop “automated web services such as highly functional agents.”
The focus here is a technical model for the web that supplies more detailed infrastructure.

4. The Service Bazaar
Microsoft and Sun seem to have a vision of the web as a bazaar of services, as well as products.
With the product model you make one large payment and get unlimited access to one product version, shipped over the web or via a physical route.
In the services model you make a per-use payment and get access to the most current version, over the web.

5. Web Services Infrastructure
Package data in self-describing documents using XML
Support messaging with Simple Object Access Protocol (SOAP) with XML documents as the fundamental messages and medium of data exchange.
Use the XML document structure to communicate with server data stores.

6. .Net Architecture Common language runtime library C# language
A set of base components
provided by the common language runtime
Networking, containers, GUI parts, …
Win Forms and Web Forms
New UI framework, simplifying UI implementation
ASP+
Active Server Pages supporting compiled server side components
ADO+
Database access components using XML and SOAP
Scripts can use common runtime library and can be compiled.

7. Common Language Runtime (CLR)
Runs bytecodes in an Intermediate Language (IL) format. This is compiled, not interpreted.
Scripts now can be compiled and can use the services and components provided by the CLR.

8. C# Language Looks a lot like Java. Differences:
A strong analogy between:
Java Virtual Machine & C# code manager
Java bytecodes & C# Intermediate Language
Java packages & CRL components and assemblies
Both have Just In Time (JIT) compilers
Both support reflection, used to obtain class information at run time
Both languages lack generics
Differences:
Java and C# do have significant differences
C# has most of the operators and keywords of C++
C# has enumerations
C# plans to add generics in the second release of Visual Studio 7
C# code supports attributes – tagged metadata

9. What can you do with C#? Build console applications
Build windows applications
Uses a process similar to Visual Basic applications.
Build windows controls
Very like creating an ActiveX control
Create web server programs using ASP
ASP pages are a mix of HTML and script.
The HTML builds a presentation in the client’s browser
The script provides associated processing on the server.
Build web controls
Provide information to users via browser and web forms
Build web services
Provide information to other applications on other machines
Build .Net components

10. Support for Components
C# is designed to support components:
Properties, methods, events, attributes, and documentation are all first-class language constructs.
Any class can publish a set of events to which objects of another class can subscribe at run time.
Attributes, defined by the designer, can be attached to classes, methods, data members, or properties.
The compiler can be asked to generate XML documentation based on class attributes.
C# integrates with COM
Can build wrappers that create COM objects out of C# assemblies.
But C# assemblies themselves have a different architecture, and use manifests instead of the registry.

11. Base Components from the CLR
The Common Language Runtime library has components for:
String handling
Mathematical operations
Containers
File and directory access
Accessing the registry
Security
Building user interfaces and handling windows messages
Network and internet programming
Database access

12. Win Forms and Web Forms
Win forms build user interfaces using techniques borrowed from Visual Basic.
Significantly simpler than Win32, MFC, or WTL windows programming.
Much less powerful in Visual Basic. I don’t know yet how powerful Win Forms are in C#.
Web forms attempt to build user interfaces based on HTML pages.
Flexible and integrates well with distributed, web-based systems
Not as powerful as MFC programming.
Can you drop down to WTL or Win32 programming? I don’t know yet.

13. ADO+
Emphasizes the Data Set, which is a disconnected, in memory, copy of part of the database, which may have multiple tables.
This is a performance improvement that minimizes locking that used to occur with ADO recordsets.
You instantiate a DataSet, populate it from the database, and work on the DataSet.
Send back only changes to the database when you are done working with the DataSet object.
Transmission back and forth now uses XML, rather than COM marshaling, as with ADO.

14. ASP+ ASP code consists of pages of HTML and script.
ASP+ code does a lot of what the ASP scripts did using attribute tags.
ASP+ pages are compiled into into a .Net class the first time the page is requested. The compiled class is cached for future requests.
ASP+ pages can be changed without stopping the web server.
“Script” part of ASP+ pages can be written in any .Net language, not just VBScript or JavaScript.
Creation of ASP+ pages is directly supported by Visual Studio 7.

15. Will we offer .Net Courses?
.Net will be introduced into the curriculum when Windows 2000 and Visual Studio 7 are installed in the ECS clusters. I hope that will be by the end of the Fall Semester.

16. When can I start using .Net?
Visual Studio 7 will probably be released this fall.
You can download the .Net framework and command line compilers for C# now.
Be careful. They are not entirely stable. I damaged part of my visual studio installation by installing the first .Net framework. I can not do command line compiles until I rebuild Visual Studio.
Books are starting to become available now – see the references on the next slide.

17. References C# Programming, Harvey et al., Wrox Press, 2000
Covers a lot of the .Net framework as well as C#.
Microsoft .Net vs. J2EE, Jim Farley,
Comparison of .Net with Java 2.0 Enterprise Edition
Deep Inside C#, An Interview with Microsoft Chief Architect Anders Hejlsberg, John Osborn,
Interview with the principal developer of C#, who also was the author of the original Turbo Pascal.