ArgDefender 2.1.0

ArgDefender

Fluent argument validation for .NET that keeps guard clauses readable and fast.

Why ArgDefender?

Fail fast: validate inputs at your code boundaries so problems surface immediately, with clear exceptions to pinpoint the offending argument.

• Fluent, chainable guards with clear exception types.
• Null-tolerant for nullable inputs; add NotNull() when you need to enforce non-null.
• Automatic parameter names; Guard.Argument(value) captures the name so you do not need to pass strings via nameof().
• Optional secure mode redacts sensitive values from exception messages.

Installation

dotnet add package ArgDefender

Supported frameworks

• net10

Quick start

using ArgDefender;

public sealed class Person
{
    public Person(string name, int age, Uri homepage)
    {
        Guard.Argument(name).NotNull().NotWhiteSpace();
        Guard.Argument(age).Min(0).Max(130);
        Guard.Argument(homepage).UriAbsolute();

        Name = name;
        Age = age;
        Homepage = homepage;
    }

    public string Name { get; }
    public int Age { get; }
    public Uri Homepage { get; }
}

Behavior

ArgDefender throws standard exceptions with consistent, predefined messages:

• Most guards throw ArgumentException and include the parameter name in the message.
• Range/comparison guards (Min, Max, InRange, etc.) throw ArgumentOutOfRangeException.
• Null enforcement (NotNull, NotAllNull) throws ArgumentNullException.

For checks that would otherwise echo values, secure: true replaces the message with "<name> is invalid.".

Examples

Guard chaining

Guard.Argument(name).NotNull().NotEmpty().MaxLength(200);

Custom messages

Guard.Argument(port).InRange(1, 65535, (value, min, max) => $"Port must be {min}-{max}.");

Nullable inputs

string? name = request.Name;
Guard.Argument(name).NotNull().NotWhiteSpace().MaxLength(40);

Secure mode

Guard.Argument(apiKey, secure: true).NotNull().NotWhiteSpace().MinLength(32);

URI checks

var homepage = new Uri("https://example.com");
var redirectUri = new Uri("/callback", UriKind.Relative);
Guard.Argument(homepage).UriHttps();
Guard.Argument(redirectUri).UriRelative();

Enum checks

var status = Status.Pending;
var permissions = Permissions.Read | Permissions.Write;
Guard.Argument(status).EnumDefined();
Guard.Argument(permissions).EnumHasFlag(Permissions.Read);

Defaults and negatives

Guard.Argument(command.Number).NotDefault().NotNegative();

For the detailed list, see docs/standard-validations.md.