5.9 Static Members

Let’s go through static Members in C# — a very useful concept for shared data and utility methods.

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📌 1. What Are Static Members?

• Static members belong to the class itself, not to any particular object.

• They are shared across all instances of the class.

• Can be fields, properties, methods, or even constructors.

Key Points

1. Accessed using the class name, not an object.

2. Useful for shared data or utility/helper methods.

3. Cannot access instance members directly inside a static member.

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📌 2. Static Fields

public class Counter
{
    public static int count = 0;  // Shared across all objects
 
    public Counter()
    {
        count++;  // Incremented every time an object is created
    }
}
 
// Usage
Counter c1 = new Counter();
Counter c2 = new Counter();
 
Console.WriteLine(Counter.count); // 2

• count is shared by all objects of Counter

• Accessed via Counter.count, not c1.count

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📌 3. Static Methods

public class MathHelper
{
    public static int Add(int a, int b)
    {
        return a + b;
    }
}
 
// Usage
int sum = MathHelper.Add(5, 3); // 8

• Add is called without creating an object

• Cannot use instance fields/properties inside a static method

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📌 4. Static Properties

public class AppSettings
{
    public static string Version { get; set; } = "1.0";
}
 
// Usage
Console.WriteLine(AppSettings.Version); // 1.0
AppSettings.Version = "1.1";
Console.WriteLine(AppSettings.Version); // 1.1

• Similar to static fields, but provides controlled access via get/set

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📌 5. Static Constructor

• Called automatically once before the first access to the class

• Used to initialize static fields

public class Config
{
    public static string AppName;
 
    static Config()
    {
        AppName = "MyApp";
        Console.WriteLine("Static constructor called");
    }
}
 
// Usage
Console.WriteLine(Config.AppName); // Static constructor called, then MyApp

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📌 6. Static Class

• Cannot be instantiated

• Can only contain static members

• Useful for utility/helper classes

public static class Utilities
{
    public static void PrintHello()
    {
        Console.WriteLine("Hello!");
    }
}
 
// Usage
Utilities.PrintHello(); // Hello!

• Cannot create objects like new Utilities()

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📌 7. Summary Table

Member Type	Access	Notes
Static Field	ClassName.FieldName	Shared by all instances
Static Method	ClassName.MethodName()	Cannot access instance members
Static Property	ClassName.PropertyName	Provides controlled access to static data
Static Constructor	Automatically called once before first use	Initialize static fields
Static Class	ClassName.MethodName()	Cannot instantiate, all members static

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✅ Tip:

• Use static members for shared data or utility methods

• Use instance members for object-specific data

• Combine with readonly to make immutable shared data