CLR:CommonLanguageRuntime (CLR), service framework (ServicesFramework) and two upper application templates-traditional Windows application template (winfoww. zdyan. com rms) and Web-oriented network application template (WebForms and WebServices) based on ASPNET.

Yes. NET framework is an environment for development, deployment and operation. NET applications, including ASP.NET, CLR and. NET framework class.

Several main components of. NET development framework: firstly, it is the foundation of the whole development framework, that is, the common language runtime and a set of basic class libraries provided by it; In terms of developing technology, NET provides a brand-new database access technology ADO.NET, as well as network application development technology ASP.NET and Windows programming technology WinForms；; As far as developing languages are concerned,. NET provides support for VB, VC++, C#, Jscript and other languages. VisualStudio.NET is a development tool and fully supports it. Net. Let's get to know them step by step: CommonLanguageRuntime, that is, commonlanguageruntime. Microsoft.NET has brought a brand-new development framework to developers, and the common language runtime is at the bottom of this framework, which is the foundation of this framework. Developers are already very familiar with the so-called C runtime, VB runtime and Jave virtual machine, while the common language runtime provides a unified running environment for multiple languages. In addition, it provides more functions and features, such as a unified and simplified programming model, so users don't have to be confused by Win32API and COM; . It avoids the problem of version and update of DLL (usually called DLL hell), thus greatly simplifying the release and upgrade of applications. Interaction between multiple languages, for example, we can even use classes written by C++ in VB; Automatic memory and resource management and so on. Based on the common language runtime, Microsoft.NET has realized the functions that these developers dream of. The code developed based on the general language runtime is called controlled code, and its running steps are as follows: first, write the source code in the programming language supported by the general language runtime, then use the compiler of the general language runtime to generate MicrosoftIntermediateLanguage, which has nothing to do with the machine, and at the same time generate the metadata required by the runtime, and then use JustInTimeCompiler to generate the corresponding machine code for execution at the code runtime. Of course, for developers, apart from so many new features provided by the common language runtime, what kind of BaseClassLibrary is the programming interface it provides for developers. This basic class library includes all aspects from input and output to data access, and provides a unified object-oriented, hierarchical and extensible programming interface. It uses the method of dot separation, which makes it very easy to find and use class libraries. For example, the root in the basic class library, whose namespace is System, and the namespace of the class library that provides data access is System.Data. When using it, developers only need to add references to the required basic class library in their own applications, and then they can use all the methods, properties and so on in this class library. Compared with traditional Windows programming, it is very easy to use and expand the basic class library, which enables developers to build network applications based on the next generation Internet efficiently and quickly. Almost all applications need to access different types of data, from simple text files to large relational databases. Microsoft.NET's technology of accessing database is ADO.NET. ADO.NET provides a set of class libraries for connecting databases, running commands and returning recordsets. Compared with ADO(ActiveXDataObject), Connection and Command objects are very similar, while ADO. NET innovation is mainly reflected in the following aspects: First, ADO.NET provides strong support for XML, which is also a major design goal of ADO.NET. In ADO.NET, XML data can be easily created and used through XMLReader, XMLWriter, XMLNavigator and XMLDocument, and W3C standards such as XSLT, DTD and XDR are supported. Addo. NET's support for XML also provides a foundation for XML to become a unified format for data exchange in Microsoft.NET. Secondly, ADO.NET introduced the concept of data set, which is a data buffer residing in memory and provides a relational view of data. Whether the data comes from a relational database or an XML document, we can use a unified programming model to create and use it. It replaces the original recordset object, improves the interactivity and expansibility of the program, and is especially suitable for distributed applications. In addition, some new objects have been introduced into ADO.NET, such as DataReader, which can be used to efficiently read data and generate read-only record sets. In short, ADO.NET made Microsoft.NET's data manipulation very convenient and efficient through a series of new objects and programming models, and closely combined with XML. ASP.NET is a network programming structure in Microsoft.NET, which makes it very convenient and efficient to build, run and publish network applications. We can learn about ASP.NET from the following aspects:

1.ASP.NET Web Form ASP.NET Web Form is designed to make it easy for developers to create web forms. It introduces the rapid development mode in VB into network development, thus greatly simplifying the development of network applications. Specifically, it can support multiple languages in ASP.NET, not only scripting languages, but all languages supported by the common language runtime can be used in ASP.NET. Code and content are separated. In the current development of ASP(ActiveServerPages), content and scripts are intertwined, which makes it difficult to maintain and upgrade. Separating them can make developers and designers work better together and improve development efficiency. In addition, by introducing server-side controls into ASP.NET, the rapid development similar to VB is applied to network development, which greatly improves the efficiency of building network forms, and the server-side controls are extensible, so developers can build their own server-side controls.

2.ASP.NET network service is the core of the next generation programmable network. It is actually a nameable network resource, which can be used to conveniently represent and use objects within the scope of the Internet, just like using COM objects today, except that the use and representation of network services are realized through SOAP (Simple Object Access Protocol) or even HTTP. In ASP.NET, it is very convenient to set up and use a network service: to set up a network service in ASP.NET is to write a file with a suffix. ASMX, just add the method you want to express in this document. Web service builders don't need to know the details of SOAP and XML, but only need to focus on their own services, which also provides a good opportunity for independent software service developers. The simplest way to use network service is to use HTTP protocol (HTTPGET or HTTPPOST), and users only need to directly access the URL of network service (. ASMX file). Of course, users can also use network services more flexibly in their own applications through SOAP.

3.ASP.NET application framework ASP.NET application is no longer to interpret scripts, but to compile and run, plus flexible buffering technology, which fundamentally improves performance; Because of ASP. NET application framework is based on the common language runtime, and publishing a network application is only a process of copying files, even the release of components. Updating and deleting network applications can directly replace/delete files; Developers can store application configuration information in XML format files, and administrators and developers can manage applications separately. Provide more diversified authentication and safety management methods; It has been greatly improved in many aspects such as reliability. Traditional Windows-based applications (WinForms) are still an indispensable part of Microsoft. NET strategy. When developing traditional Windows-based applications in Microsoft.NET, we can not only make use of existing ActiveX controls and rich Windows interfaces, but also develop them based on the common language runtime, using ADO.NET and network services, so as to realize them. NET such as avoiding DLL hell and supporting multiple languages. From the above introduction, we already know that Microsoft.NET development framework supports multiple languages, and in the current beta version, VB, C++, C# and Jscript and their deep interaction have been supported. Moreover, Microsoft supports third parties to produce compilers and development tools for Microsoft, which means that almost all programming languages on the market may be suitable for Microsoft development frameworks. In this way, developers can choose their favorite language at will, which is exactly what developers like. In particular, Microsoft introduced a brand-new C# language in Microsoft. This new object-oriented language enables developers to quickly build different applications from the bottom system level to the high-level business components. C# not only ensures powerful functions and flexibility, but also brings rapid development similar to VB to C and C++. NET, such as C# allows XML data to be mapped directly to its data type and so on. The combination of these features makes C# an excellent next-generation network programming language. At the same time, Microsoft.NET has greatly improved the original VB and C++ to make them more suitable for the development framework of Microsoft.NET. For example, VisualBasic.NET added object-oriented features, such as inheritance and structured error handling. The manageable C++ extension greatly improves the efficiency of developing Microsoft.NET applications with C++. As the next generation development tool of Microsoft, VisualStudio.NET and. NET development framework is an excellent tool for building the next generation Internet applications. At present, a beta version has been released. VisualStudio.NET has greatly improved the efficiency of developers by providing a unified integrated development environment and tools; Integrated multilingual support; Simplifies the development of the server; It provides an effective way to create and use network services, and so on. One of the main purposes of. NET framework is to make COM development easier. The most difficult thing in COM development is to deal with the basic structure of COM. Therefore, in order to simplify the development of COM. In fact, the. NET framework has automatically handled all tasks closely related to COM in the eyes of developers, including reference calculation, interface description and registration. It must be realized that this does not mean. NET framework COMponent is not a com component. Actually, COM developers using VisualStudio6.0 can call. NET framework COMponent, and in their view, the latter is more like a com component with iUnknown data. Instead, developers who use VisualStudio. NET. NET framework treats COM components as. NET framework component. In order to avoid misunderstanding, this relationship needs to be specially explained here: COM developers must manually complete most of them. NET framework developers can execute it automatically at run time. For example, the security module of COM components must be handwritten, and the memory occupied by the module cannot be managed automatically. When installing COM components, you must put the registry key into the Windows registry. For. NET framework, the runtime will automatically perform these functions. For example, the component itself is self-describing, so it can be installed without registering in the Windows registry. When COM is combined with Microsoft Transaction Server (MTS) and Distributed COM(DCOM), it becomes COM+. COM+ provides a set of middle-tier oriented services. In particular, COM+ provides process management function and database and object connection pool processing function. In future versions, it will also provide a function called partition-a more powerful process isolation function, which is specially designed for application service providers. COM+ service is mainly oriented to middle-tier application development, and mainly provides reliability and scalability for large-scale distributed applications. These services are complementary to the services provided. NET framework; These services can be accessed directly through. NET framework class. Yes. NET framework has several elements worth mentioning. The first is its security system and configuration system. The cooperation between the two systems effectively curbed the possibility of running unsafe code, and greatly reduced the challenges faced by the so-called "DLLHell" in configuring applications. Security system is a highly detailed and fact-based system, which gives developers and administrators a variety of code processing rights (not just "on" or "off"). How to realize the above permissions in the future will be decided according to the core elements of the code itself. For example, when a. NET framework application is downloaded to a system, it will apply for a set of permissions (such as write permission to a temporary directory). The runtime will collect factual information about the application (such as where it was downloaded, whether it used a valid signature, and even the accuracy of its access to the system), and decide whether to allow the application to run according to the management policy. The runtime can even tell the application that it cannot grant all the requested permissions and allow the application to decide whether to continue running. With this security system as a guarantee, many application configuration problems will be solved. One of the biggest challenges faced by developers and administrators (and end users) is version management. If after you install an application, everything is confined to a paralyzed state, and the system has been running well until then, it is likely that the newly installed application rewrites some * * * shared libraries, and it is likely to correct the program errors that the existing application is using. This happens so often that people call it "DLLHell". Yes. The. NET framework has several advanced functions that can completely eliminate the phenomenon of "DLLHell". First of all, it has a very powerful internal naming system, which can effectively prevent two libraries from being mistaken for each other because of the same name. In addition, it provides a new function called "parallel" configuration. If the newly installed application in the above example does overwrite the * * * shared library, the existing application can repair the library. When the existing application starts again, it will check all files. If it finds that the file has been changed and these changes are incompatible, it can request the runtime to extract the version it can use. Due to the powerful security system, the runtime can safely perform this operation, thus making the application complete its own repair work. In a word, based on the common language runtime, Microsoft.NET development framework provides developers with a perfect basic class library, the next generation database access technology ADO.NET and the network development technology ASP.NET. Developers can use multiple languages and VisualStudio.NET to quickly build the next generation of web applications. With the popularization of related Internet standards and technologies, it can be predicted that more and more developers will adopt this development structure to develop various next-generation Internet applications.