All 16 Exception Handling questions
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C# › Exception Handling

How do custom exception classes work in C#, and what's the recommended convention for creating one?

Intermediate

Answer

A custom exception should inherit from Exception (or a more specific built-in exception type), be named ending in 'Exception', and typically provide the standard set of constructors (parameterless, message-only, message+innerException) to remain compatible with standard exception-handling conventions and serialization.
public class InsufficientFundsException : Exception {
  public decimal ShortfallAmount { get; }
  public InsufficientFundsException(decimal shortfall)
    : base($"Insufficient funds. Short by {shortfall:C}.") {
    ShortfallAmount = shortfall;
  }
}
Real-world example Throwing a domain-specific exception (like InsufficientFundsException) that carries meaningful business context beyond a generic message string.

Common follow-ups: Why is it considered good practice to include the standard set of base constructors on a custom exception?

OOP
All 16 Exception Handling questions