How to specify a min but no max decimal using the range data annotation attribute?

How about something like this:

[Range(0.0, Double.MaxValue, ErrorMessage = "The field {0} must be greater than {1}.")]

That should do what you are looking for and you can avoid using strings.

If you are concerned about the string looking nice you could do this:

    [Range(0, Double.PositiveInfinity)]

This will have a default error message of:

The field SuchAndSuch must be between 0 and Infinity.

It seems there's no choice but to put in the max value manually. I was hoping there was some type of overload where you didn't need to specify one.

[Range(typeof(decimal), "0", "79228162514264337593543950335")]
public decimal Price { get; set; }

You can use:

[Min(0)]

This will impose a required minimum value of 0 (zero), and no maximum value.

You need DataAnnotationsExtensions to use this.

If you're working with prices, I'm sure you can safely assume nothing will cost more than 1 trillion dollars.

I'd use:

[Range(0.0, 1000000000000)]

Or if you really need it, just paste in the value of Decimal.MaxValue (without the commas): 79,228,162,514,264,337,593,543,950,335

Either one of these will work well if you're not from Zimbabwe.

You can use custom validation:

    [CustomValidation(typeof(ValidationMethods), "ValidateGreaterOrEqualToZero")]
    public int IntValue { get; set; }

    [CustomValidation(typeof(ValidationMethods), "ValidateGreaterOrEqualToZero")]
    public decimal DecValue { get; set; }

Validation methods type:

public class ValidationMethods
{
    public static ValidationResult ValidateGreaterOrEqualToZero(decimal value, ValidationContext context)
    {
        bool isValid = true;

        if (value < decimal.Zero)
        {
            isValid = false;
        }

        if (isValid)
        {
            return ValidationResult.Success;
        }
        else
        {
            return new ValidationResult(
                string.Format("The field {0} must be greater than or equal to 0.", context.MemberName),
                new List<string>() { context.MemberName });
        }
    }
}

I was going to try something like this:

[Range(typeof(decimal), ((double)0).ToString(), ((double)decimal.MaxValue).ToString(), ErrorMessage = "Amount must be greater than or equal to zero.")]

The problem with doing this, though, is that the compiler wants a constant expression, which disallows ((double)0).ToString(). The compiler will take

[Range(0d, (double)decimal.MaxValue, ErrorMessage = "Amount must be greater than zero.")]

using Range with

[Range(typeof(Decimal), "0", "9999", ErrorMessage = "{0} must be a decimal/number between {1} and {2}.")]

[Range(typeof(Decimal),"0.0", "1000000000000000000"]

Hope it will help

[Range(0.01,100000000,ErrorMessage = "Price must be greter than zero !")]

I would put decimal.MaxValue.ToString() since this is the effective ceiling for the decmial type it is equivalent to not having an upper bound.