haliphax

This StandardValidator extension will determine whether or not a given field value passes for currency. In order to do so, it must meet the following requirements:

1. It must pass decimal.TryParse()
2. It must not have more than 2 digits past the decimal point

Obviously, this does not fit all international systems—however, in my case, it works for my project (which does not require localization). The code could easily be customized to accommodate additional formats.

Note: In the code below, replace your.namespace.validators with something more suited to your particular project.

C# code:

using System.Runtime.Serialization;
using Sitecore.Data.Validators;
using System;
using Sitecore.Data.Items;
using System.Text;

namespace your.namespace.validators
{
	[Serializable]
	public class CurrencyValidator :
	Sitecore.Data.Validators.StandardValidator
	{
		public CurrencyValidator() { }

		public CurrencyValidator(SerializationInfo info, StreamingContext
		context)
		: base(info, context)
		{ }

		public override string Name
		{
			get
			{
				return ("CurrencyValidator");
			}
		}

		protected override ValidatorResult GetMaxValidatorResult()
		{
			return (GetFailedResult(ValidatorResult.Error));
		}

		protected override ValidatorResult Evaluate()
		{
			// ignore blank fields (use the Sitecore-supplied Required validator if you want blank fields to fail)
			if(ControlValidationValue == "") return ValidatorResult.Valid;
			decimal val = -1;
			decimal.TryParse(ControlValidationValue, out val);
			// value must be 0 or greater
			if (val >= 0)
			// value must not have more than 2 digits after the decimal point
			if(Math.Round(val, 2) == val)
			// valid result
			return ValidatorResult.Valid;
			// fall-through: invalid result
			Text = "The number must be a positive integer or a positive float with no more than 2 digits after the decimal point.";
			return (GetFailedResult(ValidatorResult.Error));
		}
	}
}

Create a new field-level Validation Rule item in your sitecore tree (wherever you store your rules—in this particular project, they are stored in /sitecore/System/Settings/Validation Rules/Field Rules), and set the Type field for your new rule to:

your.namespace.validators.CurrencyValidator,your.namespace.validators

Remember to swap the namespace with whatever you've chosen for your project.

Note: The version of Sitecore CMS this validator was built and tested on is 6.2.