C# is a simple, safe, stable, object-oriented programming language derived from C and C++. While inheriting the powerful functions of C and C++, it removes some of their complexity, combines Visual Studio's simple visual operations and C++'s efficient operation efficiency. With its powerful operation capabilities, unique syntax style, innovative language features, and convenient component-oriented programming support, it has become the preferred language for .NET development and has become the standard specification for ECMA and ISO.
C# and Java have surprising similarities, mainly including such as single inheritance, interface, almost the same syntax as Java and compiling into intermediate code during running. However, C# and Java have obvious differences. It draws on a feature of Delphi, which is directly integrated with COM (Component Object Model), and it is the protagonist of the .NET Windows network framework.
Using C# language, users can create traditional Windows client applications, XML Web Services, distributed components, client applications, server applications, and database applications, etc.
C# has strong grammatical expression skills and is simple and easy to learn. The brace syntax of C# allows people familiar with C, C++, or Java to get started right away. C# syntax provides many powerful functions, such as null's value types, enumerations, delegates, and direct memory access of lambda expressions, which are not available in the Java language.C# supports generic methods and types, providing better type safety and performance.C# also provides iterators that allow implementers of collection classes to define custom iterative behaviors so that they can be easily used by client code. In C# 3.0, Language Integrated Query (LINQ) expressions make strongly typed queries a top-notch language construct.
As an object-oriented language, C# supports encapsulation, inheritance, and polymorphism. All variables and methods can implement any number of excuses. Various methods of rewriting virtual methods in the parent class require the override keyword as a way to avoid accidental redefinitions. In C#, the structure is similar to a lightweight class, which is a stack-allocated type that can implement interfaces, but does not support inheritance.
In addition to these basic object-oriented principles,C# also simplifies the development of software components through several innovative language construction:
- 1. Encapsulated method signature (called "delegation"). Type-safe event notification is implemented.
- 2. Properties act as accessors for private member variables.
- 3. Properties, providing declarative metadata about runtime types.
- 4. Inline XML document comments.
- 5. Language integrated query (LINQ), providing built-in query functions across various data sources.
In C#, if you have to interact with other Windows software, such as COM objects or native Win 32 DLLs, it can be done through a process called "interoperation". Interoperability enables C# programs to complete the implementation of native C++ applications, and C# even supports pointers and "unsafe" code.
The C# generation process is simpler than C and C++ and more flexible than Java. It does not have separate header files, does not require methods and types to be declared in a specific order, and can also define any number of classes, structures, interfaces and events.
C# unique features:
1. Intermediate code.
2. Declaration in namespace. When creating a program, one or more classes are created in a namespace, and in this namespace (outside the class), there may be declaration interfaces, enumeration types and structures, etc. At this time, you must use the using keyword to refer to the content of other namespaces.
3. Basic data types. C# has a wider range of data types than C, C++ or Java. These data types are bool, byte, ubyte, short, ushort, int, uint, long, float, double, and decimal.
4. Two basic classes, one named object is the base class of all other classes, and a class named string is like object, which is part of this language.
5. Parameter passing. Methods can be declared to accept variable number of parameters. The default parameter passing method is to pass value to the basic data type. The ref keyword can be used to make a variable accept a return value through a reference pass, and the out keyword can declare the process of reference pass. Unlike ref, the out keyword can indicate that a parameter does not require an initial value.
6. Integration with COM. The biggest feature of C# for Windows programs is its seamless integration with COM, which is Microsoft's Win32 component technology. Classes written in C# can subclass an existing COM component, and the generated class may be used as a COM component.
7. Index subscript. Using indexes does not use attribute names to reference class members, but uses numbers in square brackets to reference anonymously (just as using array subscripts).
8. Agent and feedback. A proxy object includes the information required to access a specific method of a specific object. The proxy object can be moved to another place, and then type-safe calls to existing methods can be made by accessing it. One feedback method is the special case of the agent. The event keyword is used to declare a method called as a proxy when an event occurs.
Program development supported by C# language:
1. Support DOS programs (console applications)
2. Support desktop Windows Forms Application
3. Support the development of game programs
4. Support the development of web programs (authorship management system, library query system, server service program, etc.)
5. Support the development of mobile phone applications (embedded systems, etc.)
6. Support application development.
The above is a summary of the introductory knowledge points for learning C#. I hope it will be helpful to everyone in learning C# programming.