{"id":496,"date":"2022-01-10T11:11:20","date_gmt":"2022-01-10T04:11:20","guid":{"rendered":"https:\/\/csharptutorial.net\/?page_id=496"},"modified":"2022-06-03T15:01:07","modified_gmt":"2022-06-03T08:01:07","slug":"csharp-static-field-property","status":"publish","type":"page","link":"https:\/\/www.csharptutorial.net\/csharp-tutorial\/csharp-static-field-property\/","title":{"rendered":"C# Static Field & Property"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about the C# static field and static property. <\/p>\n\n\n\n

Introduction to the C# static field<\/h2>\n\n\n\n

A static field is bound to a class<\/a>, not an instance of the class. To declare a static field, you use the static<\/code> keyword. Consider the following example.<\/p>\n\n\n\n

First, define the Person<\/code> class:<\/p>\n\n\n

\/\/ Person.cs<\/span>\n\nclass<\/span> Person<\/span>\n<\/span>{\n    public<\/span> string Name;\n\n    public<\/span> Person(string name)\n    {\n        Name = name;\n    }\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In the Person<\/code> class, the Name<\/code> is an instance field that is bound to an instance of the Person<\/code> class. <\/p>\n\n\n\n
This means that each instance of the Person<\/code> class has its own Name<\/code> field with a separate value.<\/p>\n\n\n\n
Second, create two instances of the Person<\/code> class:<\/p>\n\n\n
\n\/\/ Program.cs<\/span>\n\nvar<\/span> p1 = new<\/span> Person(\"John\"<\/span>);\nvar<\/span> p2 = new<\/span> Person(\"Jane\"<\/span>);\n\nConsole.WriteLine($\"p1 Name: {p1.Name}\"<\/span>);\nConsole.WriteLine($\"p2 Name: {p2.Name}\"<\/span>);<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n
\n
\"\"<\/figure>\n<\/div>\n\n\n
In this picture, p1<\/code> and p2<\/code>  are references that refer to separate Person<\/code>‘s objects with their own name fields and values.<\/p>\n\n\n\n
Third, add a static field Count<\/code> to Person<\/code> class and initialize its value to zero:<\/p>\n\n\n
\/\/ Person.cs<\/span>\n\nclass<\/span> Person<\/span>\n<\/span>{\n    public<\/span> string Name;\n\n    public<\/span> static<\/span> int Count = 0<\/span>;\n\n    public<\/span> Person(string name)\n    {\n        Name = name;\n    }\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Unlike an instance field, the compiler creates a separate memory location to store a static field once it encounters the Person<\/code> class:<\/p>\n\n\n
\n
\"\"<\/figure>\n<\/div>\n\n\n
To access the static field Count<\/code> inside the Person<\/code> class, you reference the field directly:<\/p>\n\n\n
Count<\/code><\/span><\/pre>\n\n\n
Since the static field Count<\/code> is bound to the Person class, not an instance of the class, you cannot use the this<\/code> keyword to reference it. The following statement will result in an error:<\/p>\n\n\n
this<\/span>.Count<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Fourth, increase the value of the static field Count<\/code> by one in the constructor<\/a>:<\/p>\n\n\n
\/\/ Person.cs<\/span>\n\nclass<\/span> Person<\/span>\n<\/span>{\n    public<\/span> string Name;\n\n    public<\/span> static<\/span> int Count = 0<\/span>;\n\n    public<\/span> Person(string name)\n    {\n        Name = name;\n\n        Count++;\n    }\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Fifth, access a static field outside of the class using the ClassName.StaticField<\/code> syntax:<\/p>\n\n\n
\/\/ Program.cs<\/span>\n\nConsole.WriteLine(Person.Count); \/\/ 0<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Finally, create two instances of the Person<\/code> class. Each statement implicitly calls the Person<\/code> constructor that increases the value of the Count<\/code> static field by one:<\/p>\n\n\n
\/\/ Program.cs<\/span>\n\nConsole.WriteLine($\"Person count: {Person.Count}\"<\/span>); \/\/ 0<\/span>\n\nvar<\/span> p1 = new<\/span> Person(\"John\"<\/span>);\nvar<\/span> p2 = new<\/span> Person(\"Jane\"<\/span>);\n\nConsole.WriteLine($\"Person count: {Person.Count}\"<\/span>); \/\/ 2<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n
\n
\"C#<\/figure>\n<\/div>\n\n\n
C# static property<\/h2>\n\n\n\n
Like a static field, a static property is bound to a class, not any instances of the class. The following example redefines the Person<\/code> class with a static property Count<\/code>:<\/p>\n\n\n
class<\/span> Person<\/span>\n<\/span>{\n    public<\/span> string Name;\n\n    public<\/span> static<\/span> int Count { get; private<\/span> set; }\n\n    public<\/span> Person(string name)\n    {\n        Name = name;\n\n        Count++;\n    }\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the Count<\/code> property has a public get<\/code> accessor and a private set<\/code> accessor. This means that you can change the Count<\/code> property inside the class and access it from both inside and outside of the class.<\/p>\n\n\n\n
Summary<\/h2>\n\n\n\n
  • Use the static<\/code> keyword to define a static field or property in a class.<\/li>
  • A static field or property is bound to a class, not a specific instance of the class.<\/li><\/ul>\n
    \n\t
    \n\t\t
    Was this tutorial helpful ?<\/div>\n\t\t
    \n\t\t\t\n\t\t\t\t\n\t\t\t\t\t<\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t Yes <\/span>\n\t\t\t<\/button>\n\n\t\t\t\n\t\t\t\t\n\t\t\t\t\t<\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t No <\/span>\n\t\t\t<\/button>\n\t\t<\/div>\n\t<\/header>\n\n\t
    \n\t\t
    \n\t\t\t
    <\/div>\n\t\t\t\n\t\t\t