ស៊ីទ្រុងជ្រូក

អត្ថបទនេះស្ដីអំពី ភាសាកម្មវិធីមួយ។ ចំពោះការប្រើប្រាស់ផ្សេងទៀត សូមមើល ស៊ី-ទ្រុងជ្រូក (អសង្សយកម្ម)។

ចំណងជើងត្រឹមត្រូវនៃអត្ថបទនេះគឺ C# (ភាសាកម្មវិធី)។ អាទេសកម្ម រឺ ការលុបចោលនៃសញ្ញា# គឺដោយសារតែលក្ខខណ្ឌបច្ចេកទេស។

C# (បញ្ចេញសំឡេង ស៊ីឝាប)គឺជាភាសាកម្មវិធីពហុគំរូមួយដែលដាក់បញ្ចូលក្បួនកម្មវិធីកិច្ចការដាក់ប្រភេទខ្លាំង អាជ្ញាបញ្ជា ប្រតិវេទ មុខងារ ប្រភេទ តម្រង់កម្មវត្ថុ ពឹងផ្អែកថ្នាក់ និងតម្រង់ទៅសមាសភាគ។ វាត្រូវបានអភិវឌ្ឍដោយម៉ៃក្រូសបក្នុង.NET (ដតណិត)ដែលផ្ដើមនិងក្រោយមកបានយល់ស្របថាជាមាត្រដ្ឋានដោយស.ស.គ.អ. រឺ Ecma (ECMA-៣៣៤) និងអ.ម.អ. រឺ ISO (ISO/IEC 23270:2006)។ C# គឺជាមួយក្នុងចំណោមភាសាកម្មវិធីដេលបានរចនាសម្រាប់ហេដ្ឋារចនាសម្ព័ន្ធភាសាសាមញ្ញ។

ស៊ីឝាប (C#)

បរាទិស	ពហុគំរូ: មានរចនាសម្ព័ន្ធ អាជ្ញា តម្រង់កម្មវត្ថុ បើកព្រឹត្តិការណ៍ មុខងារ ប្រភេទ ឆ្លុះបញ្ចាំង
អំបូរ	C
រចនាដោយ	ម៉ៃក្រូសប
អភិវឌ្ឍនករ	ម៉ៃក្រូសប
ចេញដំបូង	២០០០, ១៦ ឆ្នាំកន្លងទៅ
ផ្សាយថេរ	៥.០ / សីហា 15, 2012 (2012-០៨-15)
ក្បួនកំណត់ប្រភេទ	ឋិតិវន្ត ថាមវន្ត ខ្លាំង សុវត្ថិភាព ធម្មតា សន្និដ្ឋានអន្លើៗ
វេទិកា	ហេដ្ឋារចនាសម្ព័ន្ធភាសាសាមញ្ញ
ប.ក.	Cross-platform
អាជ្ញាបណ្ណ	ព.ភ.ស.គឺជាកម្មសិទ្ធិករ អ្នកចងក្រងម៉ូណូគឺជាអ.ស.ទ.ក៣ទ្វេគុណ MIT/X១១និងបណ្ណាល័យជាអ.ស.ទ.ត.កំ២ ដតហ៊្គ្នូគឺជាអ.ស.ទ.ទ្វេគុណនិងអ.ស.ទ.ត.កំ២
កន្ទុយឈ្មោះសំណុំសារ	.cs (ដតស៊ីអ៊ែស)
ស្ថានីយ៍បណ្ដាញ	https://docs.microsoft.com/de-de/dotnet/csharp/, https://docs.microsoft.com/ja-jp/dotnet/csharp/, https://docs.microsoft.com/fr-fr/dotnet/csharp/, https://docs.microsoft.com/it-it/dotnet/csharp/ docs.microsoft.com/en-us/dotnet/csharp/, https://docs.microsoft.com/de-de/dotnet/csharp/, https://docs.microsoft.com/ja-jp/dotnet/csharp/, https://docs.microsoft.com/fr-fr/dotnet/csharp/, https://docs.microsoft.com/it-it/dotnet/csharp/
Major implementations
វីស៊្យូអ៊ែលC# .ណេតភ្វ្រែមវ៉ឺខ ម៉ូណូ ដតហ៊្គ្នូ
Dialects
Cω ស្ប៉ិក# C#ពហុសព្ទ
Influenced by
C++ អេផ្វផ្វល ជ្វា ម៉ដជូឡេ-៣ ប៉ាស់ស្កាល់វត្ថុ
Influenced
D F# ណេមម៉្រល វ៉ាល់ឡា
កម្មវិធីកិច្ចស៊ីឝាប at Wikibooks

C# ត្រូវបានទុកបម្រុងជាភាសាកម្មវិធីធម្មតា ទំនើប គោលបំណងទូទៅ តម្រែតម្រង់កម្មវត្ថុមួយ។ ក្រុមអភិវឌ្ឍន៍របស់វាគឺដឹកនាំដោយលោកអានណឺស-ហាអ៊ិចស្ពាំក។ កំណែថ្មីបំផុតគឺC#៥.០ ដែលត្រូវបានដាក់ឱ្យប្រើឡើងវិញនៅថ្ងៃ ១៥សីហា ២០១២។

គោលដៅរចនា

មាត្រដ្ឋានស.ស.គ.អ.ចុះបញ្ជីគោលដៅរចនាទាំងនេះសម្រាប់C#:

• ភាសាC#ត្រូវទុកសម្រាប់ជាភាសាកម្មវិធីធម្មតា ទំនើប គោលបំណងទូទៅ តម្រែតម្រង់កម្មវត្ថុ។
• ភាសានេះ និងប្រតិបត្តិកម្មក្នុងនោះ គួរតែផ្ដល់ជំនួយសម្រាប់បថបវិធានវិស្វកម្មវាំរទន់ដូចជា ការពិនិត្យប្រភេទខ្លាំង ការពិនិត្យព្រំលំដាប់ជួរ អង្កេតកម្មនៃការព្យាយាមដើម្បីប្រើអថេរអនាទិនីយកម្ម និងសមូហកម្មសំណល់។ ភាពមាំមួនវាំរទន់ ថេរភាព និងផលិតភាពអ្នកកម្មវិធីគឺសំខាន់។
• ភាសានេះត្រូវបានគេបម្រុងសម្រាប់ប្រើក្នុងការអភិវឌ្ឍសមាសភាពវាំរទន់ដែលសាកសមសម្រាប់ការពន្លាតទៅក្នុងបរិស្ថានដែលបានចែកចាយហើយ។
• ភាពអាចយកតាមបានក្រមប្រភពគឺសំខាន់ណាស់ ក៏ដូចជាភាពអាចយកតាមបានរបស់អ្នកកម្មវិធី ជាពិសេសចំពោះពួកអ្នកកម្មវិធីទាំងនោះដែលថ្នឹករួចហើយជាមួយស៊ី (C) និង ស៊ីបូកបូក (C++)។
• ទ្រទ្រង់ដល់អន្តរជាតូបនីយកម្មគឺមានសារៈសំខាន់ណាស់។
• C# is intended to be suitable for writing applications for both hosted and embedded systems, ranging from the very large that use sophisticated operating systems, down to the very small having dedicated functions.
• Although C# applications are intended to be economical with regard to memory and processing power requirements, the language was not intended to compete directly on performance and size with C or assembly language.

ឈ្មោះ

C-sharp musical note (left)

The name "C sharp" was inspired by musical notation where a sharp indicates that the written note should be made a semitone higher in pitch. This is similar to the language name of C++, where "++" indicates that a variable should be incremented by 1.

Due to technical limitations of display (standard fonts, browsers, etc.) and the fact that the sharp symbol (U+266F ♯ MUSIC SHARP SIGN (♯)) is not present on the standard keyboard, the number sign (U+0023 # NUMBER SIGN (#)) was chosen to represent the sharp symbol in the written name of the programming language. This convention is reflected in the ECMA-334 C# Language Specification. However, when it is practical to do so (for example, in advertising or in box art), Microsoft uses the intended musical symbol.

The "sharp" suffix has been used by a number of other .NET languages that are variants of existing languages, including J# (a .NET language also designed by Microsoft that is derived from Java 1.1), A# (from Ada), and the functional programming language F#. The original implementation of Eiffel for .NET was called Eiffel#, a name retired since the full Eiffel language is now supported. The suffix has also been used for libraries, such as Gtk# (a .NET wrapper for GTK+ and other GNOME libraries), Cocoa# (a wrapper for Cocoa) and Qt# (a .NET language binding for the Qt toolkit).

Syntax

អត្ថបទដើម: C Sharp syntax

សូមមើលផងដែរ: Syntax (programming languages)

C# មានវាក្យសម្ព័ន្ធដូចខាងក្រោម៖

• Semicolons are used to denote the end of a statement.
• Curly braces are used to group statements. Statements are commonly grouped into methods (functions), methods into classes, and classes into namespaces.
• Variables are assigned using an equals sign, but compared using two consecutive equals signs.
• Square brackets are used with arrays, both to declare them and to get a value at a given index in one of them.

Distinguishing features

Note: The following description is based on the language standard and other documents listed in the "External links" section.

By design, C# is the programming language that most directly reflects the underlying Common Language Infrastructure (CLI). Most of its intrinsic types correspond to value-types implemented by the CLI framework. However, the language specification does not state the code generation requirements of the compiler: that is, it does not state that a C# compiler must target a Common Language Runtime, or generate Common Intermediate Language (CIL), or generate any other specific format. Theoretically, a C# compiler could generate machine code like traditional compilers of C++ or Fortran.

Some notable features of C# that distinguish it from C and C++ (and Java, where noted) are:

• វាមិនមានអថេរ ឬមុខងារសកលទេ។ All methods and members must be declared within classes. Static members of public classes can substitute for global variables and functions.
• Local variables cannot shadow variables of the enclosing block, unlike C and C++.
• C# supports a strict Boolean data type, bool. Statements that take conditions, such as while and if, require an expression of a type that implements the true operator, such as the boolean type. While C++ also has a boolean type, it can be freely converted to and from integers, and expressions such as if(a) require only that a is convertible to bool, allowing a to be an int, or a pointer. C# disallows this "integer meaning true or false" approach, on the grounds that forcing programmers to use expressions that return exactly bool can prevent certain types of common programming mistakes in C or C++ such as if (a = b) (use of assignment = instead of equality ==).
• In C#, memory address pointers can only be used within blocks specifically marked as unsafe, and programs with unsafe code need appropriate permissions to run. Most object access is done through safe object references, which always either point to a "live" object or have the well-defined null value; it is impossible to obtain a reference to a "dead" object (one that has been garbage collected), or to a random block of memory. An unsafe pointer can point to an instance of a value-type, array, string, or a block of memory allocated on a stack. Code that is not marked as unsafe can still store and manipulate pointers through the System.IntPtr type, but it cannot dereference them.
• Managed memory cannot be explicitly freed; instead, it is automatically garbage collected. Garbage collection addresses the problem of memory leaks by freeing the programmer of responsibility for releasing memory that is no longer needed.
• In addition to the try...catch construct to handle exceptions, C# has a try...finally construct to guarantee execution of the code in the finally block, whether an exception occurs or not.
• Multiple inheritance is not supported, although a class can implement any number of interfaces. This was a design decision by the language's lead architect to avoid complication and simplify architectural requirements throughout CLI.
• C#, like C++, but unlike Java, supports operator overloading.
• C# is more type safe than C++. The only implicit conversions by default are those that are considered safe, such as widening of integers. This is enforced at compile-time, during JIT, and, in some cases, at runtime. No implicit conversions occur between booleans and integers, nor between enumeration members and integers (except for literal 0, which can be implicitly converted to any enumerated type). Any user-defined conversion must be explicitly marked as explicit or implicit, unlike C++ copy constructors and conversion operators, which are both implicit by default. Starting with version 4.0, C# supports a "dynamic" data type that enforces type checking at runtime only.
• Enumeration members are placed in their own scope.
• C# provides properties as syntactic sugar for a common pattern in which a pair of methods, accessor (getter) and mutator (setter) encapsulate operations on a single attribute of a class. No redundant method signatures for the getter/setter implementations need be written, and the property may be accessed using attribute syntax rather than more verbose method calls.
• Checked exceptions are not present in C# (in contrast to Java). This has been a conscious decision based on the issues of scalability and versionability.
• Though primarily an imperative language, since C# 3.0 it supports functional programming techniques through first-class function objects and lambda expressions.

ប្រព័ន្ធប្រភេទសាមញ្ញ

C# has a unified type system. This unified type system is called Common Type System (CTS).

A unified type system implies that all types, including primitives such as integers, are subclasses of the System.Object class. For example, every type inherits a ToString() method.

ចំណាត់ថ្នាក់ក្រុមប្រភេទទិន្នន័យ

CTS separates data types into two categories:

1. Value types
2. Reference types

Instances of value types do not have referential identity nor referential comparison semantics - equality and inequality comparisons for value types compare the actual data values within the instances, unless the corresponding operators are overloaded. Value types are derived from System.ValueType, always have a default value, and can always be created and copied. Some other limitations on value types are that they cannot derive from each other (but can implement interfaces) and cannot have an explicit default (parameterless) constructor. Examples of value types are all primitive types, such as int (a signed 32-bit integer), float (a 32-bit IEEE floating-point number), char (a 16-bit Unicode code unit), and System.DateTime (identifies a specific point in time with nanosecond precision). Other examples are enum (enumerations) and struct (user defined structures).

In contrast, reference types have the notion of referential identity - each instance of a reference type is inherently distinct from every other instance, even if the data within both instances is the same. This is reflected in default equality and inequality comparisons for reference types, which test for referential rather than structural equality, unless the corresponding operators are overloaded (such as the case for System.String). In general, it is not always possible to create an instance of a reference type, nor to copy an existing instance, or perform a value comparison on two existing instances, though specific reference types can provide such services by exposing a public constructor or implementing a corresponding interface (such as ICloneable or IComparable). Examples of reference types are object (the ultimate base class for all other C# classes), System.String (a string of Unicode characters), and System.Array (a base class for all C# arrays).

Both type categories are extensible with user-defined types.

Boxing and unboxing

Boxing is the operation of converting a value-type object into a value of a corresponding reference type. Boxing in C# is implicit.

Unboxing is the operation of converting a value of a reference type (previously boxed) into a value of a value type. Unboxing in C# requires an explicit type cast. A boxed object of type T can only be unboxed to a T (or a nullable T).

Example:

int foo = 42;         // Value type.
object bar = foo;     // foo is boxed to bar.
int foo2 = (int)bar;  // Unboxed back to value type.

Generics

Generics were added to version 2.0 of the C# language. Generics use type parameters, which make it possible to design classes and methods that do not specify the type used until the class or method is instantiated. The main advantage is that one can use generic type parameters to create classes and methods that can be used without incurring the cost of runtime casts or boxing operations, as shown here:

// Declare the generic class.

public class GenericList<T>
{
    void Add(T input) { }
}

class TestGenericList
{
    private class ExampleClass { }
    static void Main()
    {
        // Declare a list of type int.
        GenericList<int> list1 = new GenericList<int>();

        // Declare a list of type string.
        GenericList<string> list2 = new GenericList<string>();

        // Declare a list of type ExampleClass.
        GenericList<ExampleClass> list3 = new GenericList<ExampleClass>();
    }
}

Preprocessor

C# features "preprocessor directives" (though it does not have an actual preprocessor) based on the C preprocessor that allow programmers to define symbols, but not macros. Conditionals such as #if, #endif, and #else are also provided. Directives such as #region give hints to editors for code folding.

public class Foo
{
    #region Constructors
    public Foo() {}
    public Foo(int firstParam) {}
    #endregion

    #region Procedures
    public void IntBar(int firstParam) {}
    public void StrBar(string firstParam) {}
    public void BoolBar(bool firstParam) {}
    #endregion
}

Code comments

C# utilizes a double slash (//) to indicate the rest of the line is a comment. This is inherited from C++.

public class Foo
{
    // a comment
    public static void Bar(int firstParam) {}  // also a comment
}

Multi-line comments can start with slash-asterisk (/*) and end asterisk-slash (*/). This is inherited from standard C.

public class Foo
{
    /* A Multi-Line
       comment  */
    public static void Bar(int firstParam) {}
}

XML documentation system

C#'s documentation system is similar to Java's Javadoc, but based on XML. Two methods of documentation are currently supported by the C# compiler.

Single-line documentation comments, such as those commonly found in Visual Studio generated code, are indicated on a line beginning with ///.

public class Foo
{
    /// <summary>A summary of the method.</summary>
    /// <param name="firstParam">A description of the parameter.</param>
    /// <remarks>Remarks about the method.</remarks>
    public static void Bar(int firstParam) {}
}

Multi-line documentation comments, while defined in the version 1.0 language specification, were not supported until the .NET 1.1 release. These comments start with slash-asterisk-asterisk (/**) and end asterisk-slash (*/).

public class Foo
{
    /** <summary>A summary of the method.</summary>
     *  <param name="firstParam">A description of the parameter.</param>
     *  <remarks>Remarks about the method.</remarks> */
    public static void Bar(int firstParam) {}
}

Note there are some stringent criteria regarding white space and XML documentation when using the slash/asterisk/asterisk (/**) technique.

This code block:

/**
 * <summary>
 * A summary of the method.</summary>*/

produces a different XML comment from this code block:

/**
 * <summary>
   A summary of the method.</summary>*/

Syntax for documentation comments and their XML markup is defined in a non-normative annex of the ECMA C# standard. The same standard also defines rules for processing of such comments, and their transformation to a plain XML document with precise rules for mapping of CLI identifiers to their related documentation elements. This allows any C# IDE or other development tool to find documentation for any symbol in the code in a certain well-defined way.

Libraries

The C# specification details a minimum set of types and class libraries that the compiler expects to have available. In practice, C# is most often used with some implementation of the Common Language Infrastructure (CLI), which is standardized as ECMA-335 Common Language Infrastructure (CLI).

"Hello world" ឧទារហណ៍

The following is a very simple C# program, a version of the classic "Hello world" example:

using System;

class Program
{
    static void Main()
    {
        Console.WriteLine("Hello world!");
    }
}

The effect is to write the following text to the output console:

Hello world!

បន្ទាត់នីមួយៗមានគោលបំណង៖

using System;

The above line of code tells the compiler to use System as a candidate prefix for types used in the source code. In this case, when the compiler sees use of the Console type later in the source code, it tries to find a type named Console, first in the current assembly, followed by all referenced assemblies. In this case the compiler fails to find such a type, since the name of the type is actually System.Console. The compiler then attempts to find a type named System.Console by using the System prefix from the using statement, and this time it succeeds. The using statement allows the programmer to state all candidate prefixes to use during compilation instead of always using full type names.

class Program

Above is a class definition. Everything between the following pair of braces describes Program.

static void Main()

This declares the class member method where the program begins execution. The .NET runtime calls the Main method. (Note: Main may also be called from elsewhere, like any other method, e.g. from another method of Program.) The static keyword makes the method accessible without an instance of Program. Each console application's Main entry point must be declared static. Otherwise, the program would require an instance, but any instance would require a program. To avoid that irresolvable circular dependency, C# compilers processing console applications (like that above) report an error, if there is no static Main method. The void keyword declares that Main has no return value.

Console.WriteLine("Hello world!");

This line writes the output. Console is a static class in the System namespace. It provides an interface to the standard input, output, and error streams for console applications. The program calls the Console method WriteLine, which displays on the console a line with the argument, the string "Hello world!".

A GUI example:

using System.Windows.Forms;

class Program
{
    static void Main()
    {
        MessageBox.Show("Hello world!");
    }
}

This example is similar to the previous example, except that it generates a dialog box that contains the message "Hello world!" instead of writing it to the console.

Standardization and licensing

In August 2000, Microsoft Corporation, Hewlett-Packard and Intel Corporation co-sponsored the submission of specifications for C# as well as the Common Language Infrastructure (CLI) to the standards organization Ecma International. In December 2001, ECMA released ECMA-334 C# Language Specification. C# became an ISO standard in 2003 (ISO/IEC 23270:2003 - Information technology — Programming languages — C#). ECMA had previously adopted equivalent specifications as the 2nd edition of C#, in December 2002.

In June 2005, ECMA approved edition 3 of the C# specification, and updated ECMA-334. Additions included partial classes, anonymous methods, nullable types, and generics (similar to C++ templates).

In July 2005, ECMA submitted the standards and related TRs to ISO/IEC JTC 1 via the latter's Fast-Track process. This process usually takes 6–9 months.

The C# language definition and the CLI are standardized under ISO and Ecma standards that provide reasonable and non-discriminatory licensing protection from patent claims. However, Microsoft uses C# and the CLI in its Base Class Library (BCL) that is the foundation of its proprietary .NET framework, and which provides a variety of non-standardized classes (extended I/O, GUI, Web services, etc.). Some cases where Microsoft patents apply to standards used in the .NET framework are documented by Microsoft and the applicable patents are available on either RAND terms or through Microsoft's Open Specification Promise that releases patent rights to the public, but there is some concern and debate as to whether there are additional aspects patented by Microsoft that are not covered, which may deter independent implementations of the full framework.

Microsoft has agreed not to sue open source developers for violating patents in non-profit projects for the part of the framework that is covered by the OSP. Microsoft has also agreed not to enforce patents relating to Novell products against Novell's paying customers with the exception of a list of products that do not explicitly mention C#, .NET or Novell's implementation of .NET (The Mono Project). However, Novell maintains that Mono does not infringe any Microsoft patents. Microsoft has also made a specific agreement not to enforce patent rights related to the Moonlight browser plugin, which depends on Mono, provided it is obtained through Novell.

In a note posted on the Free Software Foundation's news website in June 2009, Richard Stallman warned that he believes that "Microsoft is probably planning to force all free C# implementations underground some day using software patents", and recommended that developers avoid taking what he described as the "gratuitous risk" associated with "depend[ing] on the free C# implementations". The Free Software Foundation later reiterated its warnings, claiming that the extension of Microsoft Community Promise to the C# and the CLI ECMA specifications would not prevent Microsoft from harming free implementations of C#, because many specific Windows libraries included with .NET or Mono were not covered by this promise.

Implementations

The reference C# compiler is Microsoft Visual C#, which is closed-source.

Other C# compilers exist, often including an implementation of the Common Language Infrastructure and the .NET class libraries up to .NET 2.0:

• The Mono project provides an open source C# compiler, a complete open source implementation of the Common Language Infrastructure including the required framework libraries as they appear in the ECMA specification, and a nearly complete implementation of the Microsoft proprietary .NET class libraries up to .NET 3.5. As of Mono 2.6, no plans exist to implement WPF; WF is planned for a later release; and there are only partial implementations of LINQ to SQL and WCF.
• The DotGNU project also provides an open source C# compiler, a nearly complete implementation of the Common Language Infrastructure including the required framework libraries as they appear in the ECMA specification, and subset of some of the remaining Microsoft proprietary .NET class libraries up to .NET 2.0 (those not documented or included in the ECMA specification, but included in Microsoft's standard .NET Framework distribution).
• Microsoft's Rotor project (currently called Shared Source Common Language Infrastructure) (licensed for educational and research use only) provides a shared source implementation of the CLR runtime and a C# compiler, and a subset of the required Common Language Infrastructure framework libraries in the ECMA specification (up to C# 2.0, and supported on Windows XP only).

សូមមើលផងដែរ

C# topics C# syntax Comparison of C# and Java Implementations Microsoft Visual C# Oxygene Sing#

IDEs Microsoft Visual Studio Microsoft Visual Studio Express (freeware) MonoDevelop Morfik SharpDevelop Turbo C Sharp

អំណានបន្ថែម

• Drayton, Peter; Albahari, Ben; Neward, Ted (2002). C# Language Pocket Reference. O'Reilly. ល.ស.ប.អ. 0-596-00429-X. 
• Petzold, Charles (2002). Programming Microsoft Windows with C#. Microsoft Press. ល.ស.ប.អ. 0-7356-1370-2. 

តំណភ្ជាប់ក្រៅ

• C# Language Specification (from MSDN)
• C# Language Specification (hyperlinked, C# Online.NET) Archived February 11, 2010, at the វេយប៊ែខ ម៉ាស៊ីន.
• C# Programming Guide (MSDN)
• Download C# Express
• ISO C# Language Specification.
• Microsoft Visual C# .NET
• QuiteCode C# Development Archived November 9, 2012, at the វេយប៊ែខ ម៉ាស៊ីន.