Definitions of commonly used reference namespaces in asp.net

Using System; // introduces the core namespace, which is the basis of all classes
Using System. Collections. Generic; // introduces the set class namespace, which can use collection classes such as Generic classes.
Using System. ComponentModel; // introduce the ComponentModel namespace
Using System. Data; // introduce the Data operation namespace, which can use datasets such as DataSet
Using System. Drawing; // introduce the Drawing namespace to use a class such as Color --- image
Using System. Text; // introduces the Text operation namespace, which can use classes such as StringBuilder and character operations.
Using System. Windows. Forms; // introduces the form namespace and supports Forms-related classes.
Using System. Text; // Text operation
Using Microsoft. Win32; // perform registry operations
Using System. Collections; // use Arraylist
Using System. Security. Cryptography; // encryption and decryption
Using System. IO; // File Operations
Using System. Runtime. InteropServices; // Call DLL DllImport
Using System. Management; // obtain hardware information
Using System. Net; // used to obtain the IP address
Using System. Net. NetworkInformation; // used for ping
Using System. Text. RegularExpressions; // regular
Using System. Data. SqlClient; // SQL database operation
Using Microsoft. VisualBasic; // used in simplified to traditional Chinese
Using System. Web; // html UrlEncode