How to guard against "not one of"

[patrickiel]

Is there already a way to check if an element occurs in a collection, something like:

var city = "Rome";
Guard.Against.NotOneOf(city, nameof(city), new [] {"Berlin", "New York" "Paris"}); //  => throws Exception

[amal-stack]

Currently, there is a Guard.Against.InvalidInput() available which can be used like this:

Guard.Against.InvalidInput(city, nameof(city), c => new [] {"Berlin", "New York", "Paris" }.Any(x => x.Equals(c)));

OR:

Guard.Against.InvalidInput(city, nameof(city), c => c is "Berlin" or "New York" or "Paris", "Hi");

Also, it not that hard to define your own extension method:

public static class GuardClauseExtensions
{
	public static T NotOneOf<T>(this IGuardClause g, T input, IEnumerable<T> values, string parameterName, string message = null)
	{
		if (values.Any(v => v.Equals(input))) 
		{
			throw new ArgumentException(string.IsNullOrWhiteSpace(message) ? "The argument value is not allowed" : message, parameterName); 	
		}
		return input;
	}
}

Now you have your very own:

Guard.Against.NotOneOf(city, new [] {"Berlin", "New York", "Paris" }, nameof(city));