C# Static Constructor

In C#, a static constructor is a special type of constructor that is used to initialize the static members of a class before any static methods are called or any static properties are accessed. This guide explores the syntax, usage, and considerations of static constructors in C#.

Syntax

public class MyClass
{
    // Static constructor
    static MyClass()
    {
        // Initialization code for static members
    }
    
    // Other members of the class
    // ...
}

Example

public class Logger
{
    // Static variable to track the number of log entries
    private static int logCount;

    // Static constructor to initialize static members
    static Logger()
    {
        logCount = 0;
        Log("Logger initialized.");
    }

    // Static method to log messages
    public static void Log(string message)
    {
        Console.WriteLine($"[LOG #{++logCount}] {message}");
    }
}

class Program
{
    static void Main()
    {
        Logger.Log("Application started.");
    }
}

Output

The output will be log messages indicating that the logger is initialized and that the application has started.

Explanation

• A static constructor is declared using the static keyword before the constructor definition.
• The static constructor is called automatically before any static members are accessed or any static methods are called.
• In the example, the Logger class has a static constructor that initializes a static variable and logs a message.

Use

Use a static constructor in C# when:

• You need to perform one-time initialization of static members.
• Initialization code for static members depends on certain conditions.
• You want to ensure that static members are initialized before their first use.

Important Points

• A static constructor does not take any parameters and cannot be called explicitly.
• Only one static constructor is allowed in a class.
• Static constructors are called automatically before any static members are accessed or any static methods are called.

Summary

C# static constructors provide a mechanism for initializing static members of a class before their first use. They are useful for performing one-time initialization tasks and ensuring that static members are in a valid state. Understanding when and how to use static constructors can contribute to writing robust and well-organized C# code.