Static constructor

Context: A static constructor initializes static fields or performs one‑time setup. It is called automatically before the first static member access or first instance creation.

Syntax

class ClassName
{
    static ClassName()
    {
        // initialization code
    }
}

Characteristics

• No parameters.
• No access modifiers (implicitly private).
• Cannot be called directly.
• Runs at most once.

Example

public class Config
{
    public static readonly string ConnectionString;
    static Config()
    {
        ConnectionString = LoadFromFile();
    }
    private static string LoadFromFile() => "Server=...";
}

Order of Execution

1. Static constructor runs.
2. Then instance constructors (if creating instances).

Exceptions

If a static constructor throws an exception, the type becomes unusable.