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There is a form labeled Runat = "Server" attribute, which means tells ASP.NET to change The form will return data to use in server code. DROPDOWNLIST in the form, button (equivalent to an HTML INPUT TYPE = "Button), and a DataGrid used to display information. The button is used OnClick events identify the name of the server-side code so that the user runs these code when the user clicks it. It is worth noting that the onclick event here is not the client's DHTML onClick event. Because the control is a server-side control (Runat = " Server "), so the event will work in the server's code. if not page.ispostback kiln stat (" CA "

A very important feature of END IF Web Control is that they will remain in the process of page, so we don't have to fill them again.ispostback feature allows us to identify whether the page is loaded for the first time, or if we Data has been returned to the server. Know the .NET Framework .NET Framework content, mainly several parts: 1 On this platform, you can write the INTERNET and supported on the Internet, and these applications accept such as XML, HTTP, and SOAP has an open standard. 2 provides some very important and powerful application development technologies, such as Windows Forms that can be used to create a typical GUI application, and of course also include ASP.NET for creating grid applications. 3 A wide range of class libraries can provide extensive support for data access (relational and XML), directory services, and messages. (I am more unfamiliar with the directory service and message queue so far) 4 This platform There is a base class library that contains hundreds of classes that are used to perform regular tasks such as file operations, registry access, security, threads, and utilizing regular expressions search text. (Regular expression ??) 5 Do not exist language discriminatory, can support any language very fair. 6 has downwardly compatibility, which provides good interoperability support for existing components written for you or third parties. 7 There is a platform that is called public language, and the CLR runs a separate code running and management environment. CLR ensures the security execution of the code, and it also provides an abstract layer on the operating system, indicating that .NET Framework Each element can run on a variety of operating systems and devices. (Some of them here !!) Namespaces have the following two main functions: 1 Type of related types: For example, System.Web contains all management webs The requested low-level ASP.NET class. The System.Web.ui contains all the classes that actually displays the UI, while system.Web.hosting contains classes that help the master ASP.NET in IIS or other applications. 2 Reduce Name Conflict Note: Namespaces Do not physically packets the type because a namespace can automatically input commonly used names in different assemblies (DLLS and EXES) ASP.NET to ASP.NET Page. You can use the namespace as a directory. However, they contain the class rather than files. But a namespace called AB does not mean there is a namespace named B. Public language specification (Comman) Language Specification, CLS) Type System.Boolean System.byte Indicates unsigned byte values ​​(positive intensity between 0-255) System.Char Unicode character value system.datetime data and time value System.Decimal use 28 important purposes The number represents the positive and negative value system.double 64-bit, double-precision floating point digital system.int16 16-bit with symbol integer system.int32 32 ... system.int64 64 ... system.sbyte 8-bit with symbolic integer (-128 ~ 127) SYSTEM.SINGLE 4-bit, single-precision floating point digital system.timespan time period, or negative or negative system.string Unicode string System.Array one-dimensional number of group System.Object All other types of inheritance of basic types