ASP. NET prerequisites (3)

C # features: 1. C # code runs in the environment provided by. NET Framework, and direct memory operations are not allowed, enhancing the system security. 2. Pointers are not recommended for C #. To use pointers, you must add the unsafe modifier and use the/unsafe parameter during compilation. 3. Unified Type System. All C # types inherit from a unique root type object. 4. Use C # to build robust applications. C # garbage collection automatically recycles the memory occupied by objects that are no longer used; Exception Handling; type security design avoids uninitialized variables and array indexes exceeding the boundary. 5. Fully supports component programming. It is easy to create and use components of these software. Framework Common namespace System: provides basic classes, such as String classes that provide String operations. System. Configuration: provides data classes for processing Configuration files. For example, you can obtain the ConnectionStringSettings class of the database connection string in the web. config file. System. Data: provides access to the ADO. NET class, such as the DataSet class we commonly use (providing Data cache ). System. Ling: Provides the classes and interfaces for querying using LINQ. System. web: provides classes and interfaces for communication between the browser and the server, such as the HttpRequest class used to read the client. System. Web. Security: provides a class for implementing ASP.net Security on the Web server. System. Web. UI: Provides the class and interface used to create the user interface of an ASP.net website, such as the Page class of each Web form. System. Web. UI. Htmlcontrols: allows you to create HTML server controls on the Web forms page. System. Web. UI. WebControls: provides a Web server control class for wearing Web forms. System. Xml. Linq: provides a class for the use of LINQ to XML. HTML server control, a standard ASP. NET control, visualizes all html tags so that the program can directly control the HTML control. To program the html control, we need to convert the XHTML control into an html server control, that is, add runat = "server" to the control property ". If only html markup elements are used, the Web form access is implemented by the browser. Html controls and Html server controls appear to improve ASP. NET control. Web Server Control: it does not correspond to XHTML elements. It can describe the appearance, operation methods, and behavior of the elements, and ASP. NET determines how to output the page. After watching the instructor's ASP.net control video, I know that Web server controls can be divided into standard controls: common controls in addition to forms (forms can also be seen as special controls, for example, buttons, text box drop-down boxes, and calendar of usage classes. Data Control: connects to the database and displays data in the data. GridViewDataList. Verification control: used to control user information input. Navigation Control: used for website navigation. Logon controls such as TreeView Menu: used for Website user registration and user management. WebParts control: website portal, Custom User Interface. The AJAXExtensions control is used to update the partial information of a page instead of the whole page. Custom Controls: extends system functions to maintain a uniform style of the website. Comparison: HTML controls consume less resources, but cannot interact with the background. To interact with each other, You need to convert it into an HTML Server Control. The Web server control needs to be translated into HTML control during compilation and then transmitted to the browser, which consumes server resources.