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guard clause

A check at the top of a method that throws if an argument is bad.

A guard clause validates a precondition on entry and throws (for example ArgumentNullException.ThrowIfNull) before any work is done.

Examples

  • if (quantity <= 0) throw new ArgumentOutOfRangeException(nameof(quantity)); at the top of a method refuses bad input before any work starts.

See also

exception invariant input validation
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