Variable Scopes in C#

Ravi Vishwakarma 1133 10 Jun 2024

1 Answers

Ravi Vishwakarma 10 Jun 2024

In C#, variable scope refers to the accessibility and lifetime of variables within a program.

Here are the common variable scopes in C#:

Global Scope: Variables declared outside of any method, typically at the class level, have global scope. They are accessible from any method within the class.

class MyClass {
    int globalVariable = 10; // Global variable

    void SomeMethod() {
        // globalVariable is accessible here
    }
}

Local Scope: Variables declared within a method have local scope. They are accessible only within the method where they are declared.

class MyClass {
    void SomeMethod() {
        int localVar = 20; // Local variable
        // localVar is accessible only within SomeMethod
    }
}

Block Scope: Variables declared within a block of code (within curly braces {}) have block scope. They are accessible only within that block.

class MyClass {
    void SomeMethod() {
        {
            int blockVar = 30; // Block variable
            // blockVar is accessible only within this block
        }
        // blockVar is not accessible here
    }
}

Class Scope (Static Variables): Static variables declared within a class have class scope. They are accessible to all instances of the class.

class MyClass {
    static int staticVar = 40; // Static variable

    void SomeMethod() {
        // staticVar is accessible here
    }
}

Method Parameters: Parameters passed to a method have scope within that method.

class MyClass {
    void SomeMethod(int parameter) {
        // parameter is accessible within SomeMethod
    }
}

Lambda Expressions and Anonymous Methods: Variables used within lambda expressions and anonymous methods have access to variables in the outer scope, but they must be effectively final (cannot be modified within the lambda/anonymous method).

class MyClass {
   int outerVar = 50;
   void SomeMethod() {
       Action action = () => {
           // outerVar is accessible here
           // However, if outerVar is modified here, it must be effectively final
       };
   }
}

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Variable Scopes in C#

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