.NET Framework Architecture Common Language Runtime C++ JScript Common Language Specification Visual Studio.NET ASP.

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1 Page 1.NET Framework Architecture Common Language Runtime VB C++ C# JScript Common Language Specification ASP.NET Windows Forms ADO.NET and XML Base Class Library Common Language Runtime Windows COM+ Services Visual Studio.NET Manages running code Verifies type safety Provides garbage collection, error handling Code access security for semi-trusted code Provides common type system Value types (integer, float, user defined, etc) Objects, Interfaces Provides access to system resources Native API, COM interop, etc. Common Language Runtime Exception handling IL to Native Compilers Base Class Library Support Thread Support Type Checker Security Engine Code Manager Class Loader COM Marshaler Exception Manager Debug Engine Garbage Collector The CLR supports a standard exception-handling mechanism that works across all languages. Filters (lowest level) exceptions: [C#] try { //Some code that access a file catch(filenotfoundexception e) { Console.WriteLine("[Data File Missing] {0", e); Prepare state for exception

2 Page 2 Security support Debugging support The CLR checks to make sure that: The code is safe to execute The code is not breaching any security requirements The security engine also supports: Code-access security Declarative security checks Specified through administrative configuration or via attributes Imperative security checks Method code enforces security requirements The provided API for debuggers contains: Support for controlling program execution Breakpoints Exceptions Control flow etc. Interoperation Support The Microsoft.NET Framework promotes interaction with: COM components COM+ services External type libraries etc. How to bridge the gap: COM Interop facility is a bridge between COM and the CLR Platform Invoke (P/Invoke) facility makes it possible to call Windows API functions What is Assemblies Collection of functionality that is built versioned and deployed as a single implementation unit. The manifest: ( use MSIL disassembler Ildasm.exe to view) Establishes the identity, version, culture and digital signature. Defines what files are included in the assembly Specifies the types and resources that make up the assembly, included those that are exported from the assembly. Itemizes the compile-time dependencies on other assemblies. Specifies the set of permissions required for the assembly to run properly. AssemblyInfo.cs sets the attributes

3 Page 3 Single vs Multifile Private Assemblies Used by a single application Stored in the same application directory as the application Name does only need to be unique within the application scope Guaranteed that the application will run with the bits it was built with Shared Assemblies Signing An Assembly Used by many applications at the same time Must have a cryptographically unique strong name Deployed in the global assembly cache %windir%\assembly Calculus.dll IL Metadata Hash PE File Hash Value Signed with private key RSA Digital Signature Manifest Assembly files (self & RUT.mod) Public assembly types (self & RUT.mod) Public Key Embedded in PE File Public Key RSA Digital Signature Embedded in PE File

4 Page 4 Satellite Assemblies How the Runtime Locates Assemblies en sv.net PE File en-us Main code Class Loader Verifier JIT Managed Native Code Zh-CN One core assembly with the code Different resource assemblies for each culture CLR s Virtual Execution Engine JIT Compilers Versioning And Policy How Assembly References are Resolved part 1 Default: Bind to version built against Can be overridden with policy Application-specific policy Publisher policy Administrator policy or machine.config <dependentassembly> <assemblyidentityname="myasm" publickeytoken="e9b4c ede8" /> <bindingredirect oldversion=" " newversion=" "/> </dependentassembly> 1. Determines the correct assembly version by examining applicable configuration files. 1. Check the application configuration file for information that overrides the version information stored in the calling assembly s manifest. 2. Examines the publisher policy file installed in the GAC with the assembly. 1. May be overridden with <publisherpolicy apply= yes no > in the app config. 3. Checks the machine configuration called Machine.config located in the config subdirectory of the run-time installation. The version presented here is final and cannot be overridden. 2. If the assembly has been bound to before, use the previously loaded assembly.

5 Page 5 How Assembly References are Resolved part 2 Execution in the CLR 3. Checks the GAC for the assembly, if found, use it. 4. Probes for the assembly in the following steps: 1. If configuration and publisher policy do not affect the original reference and the request was made using Assembly.LoadFrom(), then use this information 2. If a <codebase> is found in the application configuration file then use it, if not found at that specified location the request fails. 3. Further probing using application base, culture, name and private binpath. 5. If not found ask windows installer to install it. It acts as an install on demand feature. CLR s Virtual Execution Engine JIT Compiler Call to uncompiled code Execution Verifier Managed Native Code Execution Support And Management Class Loader Class Libraries (IL & Metadata).NET Framework Architecture.NET Framework Namespace VB C++ C# JScript Common Language Specification ASP.NET Windows Forms ADO.NET and XML Base Class Library Common Language Runtime Windows COM+ Services Visual Studio.NET Services Description Discovery Protocols Caching Configuration ADO Design Collections Configuration Diagnostics Globalization System.Web System.Data UI HtmlControls WebControls Security SessionState SQL SQLTypes IO Net Reflection Resources System Security ServiceProcess Text Design Drawing2D Imaging XSLT XPath Threading System.WinForms ComponentModel System.Drawing Printing Text System.Xml Serialization Runtime InteropServices Remoting Serialization

6 Page 6 Language Interoperability A Unified Programming Model The CLR specifying and enforcing a common type system Inherit implementation from other types implemented in other languages Debuggers, profilers and other tools requires only to understand one environment, the MSIL Exceptions can be thrown across languages RAD, Composition, Delegation Consistent API availability regardless of language and programming model.net Framework Subclassing, Power, Expressiveness Stateless, Code embedded in HTML pages VB Forms MFC/ATL ASP Windows API Languages that Support.NET Advanced multi-language features Cross language inheritance, exceptions Over 20 languages support.net APL Python Cobol Scheme Component Pascal SmallTalk Eiffel Standard ML Haskell C++ Mercury VB Oberon JScript Perl C# Windows Forms Uses virtual methods to override message responses No message loop Component model that supports events MyButton.Click += new EventHandler (OnButtonClicked); private void OnButtonClicked (object sender, EventArgs e) { MessageBox.Show ("Click!"); Event is using delegates as function pointers Main form is started and then it is up to the components to fire events

7 Page 7 Programming model Organization Organized in hierarchical namespaces Unified type system Everything is an object Boxing converts value types to objects No need for special variant type Component Oriented Properties, methods & events are 1st class Design-time functionality Example Windows API HWND hwndmain = CreateWindowEx( 0, "MainWClass", "Main Window", WS_OVERLAPPEDWINDOW WS_HSCROLL WS_VSCROLL, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, (HWND)NULL, (HMENU)NULL, hinstance, NULL); ShowWindow(hwndMain, SW_SHOWDEFAULT); UpdateWindow(hwndMain);.NET Framework Form form = new Form(); form.text = "Main Window"; form.show(); Everything Is An Object Everything Is An Object Traditional views of primitive types C++, Java: They re magic Smalltalk, Lisp: They re full-blown objects The.NET Framework unifies with no performance cost Deep simplicity throughout system Improved extensibility and reusability New primitive types: Decimal, SQL Collections, etc., work for all types Boxing Allocates box, copies value into it Unboxing Checks type of box, copies value out Dim i As Integer = 123 Dim o As Object = i Dim j As Integer = CInt(o) int i = 123; object o = i; int j = (int)o; i o j System.Int32

8 Page 8 From COM to.net From COM to.net COM Registration GUIDs.IDL files HRESULTs IUnknown AddRef/Release CoCreateInstance QueryInterface.NET self describing components hierarchical namespaces source code to metadata structured exceptions Root object class Garbage collector new operator Type.GetInterface No registration required Code is completely self-describing Simply xcopycomponents to application directory Zero-impact install Installing one application will not affect another Side-by -side execution Multiple component versions can co-exist Integration with COM Evolution of COM Deploy.NET classes as COM objects Register with RegAsm.exe COM objects can be imported No ref counting or COM API needed.net classes utilize COM+ services Transactions, Object pooling, etc Easily call system functions No marshaling for common cases COM MTS COM+

9 Page 9 Overview of COM+ Services Object Pooling Some COM+ Services: Transactions Object Pooling Queued Components (MSMQ) Security For a class to exploit COM+ Services, it must: Derive from the ServicedComponent class Pools are: A group of resources. Shared between clients. Methods used for object pooling in.net: CanBePooled(), lets you tell COM+ whether your object can be pooled when this method is called. Activate( ) and Deactivate( ) to perform initialization and cleanup. Transactions Collections of operations that form a single logical unit of work are called transactions. Transaction must be atomic (i.e., either all or none of the operations in the transaction are completed). By taking advantage of COM+ Services transactions are easily implemented in.net (as we shall see). Attribute-Based Programming Attributes are placed to signal characteristics about the code Either predefined or custom Interceptor programs look for special attributes and provide additional service if they are present. Used for accessing COM+ Services from within the.net framework. The programmer does not need to know the details of how this is implemented to use COM+ Services. The.NET Reflection API can be used to implement

10 Page 10 Example: Transactions (C#) Example: Transactions (alternative C#) Example adapted from O Reillys.NET Framework Essentials using System; using System.EnterpriseServices; // Installation options omitted [Transaction(TransactionOption.Required] Public class Customer : ServicedComponent { public void Add(...) { try { // Add new customer to the system and update db s ContextUtil.SetComplete(); // Commit catch(exception e) { ContextUtil.SetAbort(); Example adapted from O Reillys.NET Framework Essentials using System; using System.EnterpriseServices; // Installation options omitted [Transaction(TransactionOption.Required] Public class Customer : ServicedComponent { [AutoComplete] public void Add(...) { // Add new customer to the system and update db s Overview of the Exercises Exercise Windows Application Web Application Private Assembly Shared Assembly Web Service Goal: Get to know WinForms and how to create applications in.net using C# Requirements Must have Visual Studio.NET and the framework Prerequisites Know C++/Java or C# Deliverable A simple window based application

11 Page 11 Exercise 1 Exercise 2 Example view from exercise 1 Goal: Implement an interface that will be used in the following labs Add a strong name to the interface and put it in the GAC Get to know private assemblies Requirements Lab 1 finished Deliverable An assembly that provide a common interface for the successive exercises A private assembly that use the common interface Useful tools Useful Tools COM Interoperability TlbImp.exe Imports a COM type library into a proxy.net assembly RegAsm.exe Enters a.net component into the registry TlbExp.exe Exports a.net component s type information AxImp.exe Creates a.net proxy for an ActiveX control so that the control can be used in a.net WinForm Class Viewer WinCV.exe Used to view classes available in the GAC including all base classes CLR resource loading Fuslogvw.exe helps to analyze the resource loading process Assembly management XML ildasm.exe examines assemblies and shows the manifest Gacutil.exe adds and removes assemblies to the Global Assembly Cache sn.exe generates and manages private and public keys XML Al.exe Assembly generation utility is used to generate assemblies with manifests and key manipulations NGEN.EXE The native Image Generator creates a native image and installs it in the cache allowing assemblies to load faster XSD.exe Used to work with XML Schema Definitions For example: Classes to XSD, XML to XSD.NET Configuration Mscorcfg.msc manages publication polices and assemblies

12 Page 12 Additional Resources msdn.microsoft.com/net/ msdn.microsoft.com/msdnmag/netindex.asp NET Framework Essentials THuan Thai & Hoang Q. Lam, O REILLY Source for many papers/tutorials/tools etc.