Dynamic Range Validation in ASP.NET MVC 2
I am using ASP.NET MVC2 and trying to validate my view models using the attributes in System.ComponentModel.DataAnnota开发者_开发技巧tions namespace.
How can I dynamically set the permitted valid range of a RangeAttribute? For example, if I want to validate that a date entered is within an expected range.
This doesn't compile:
[Range(typeof(DateTime),
DateTime.Today.ToShortDateString(),
DateTime.Today.AddYears(1).ToShortDateString())]
public DateTime DeliveryDate { get; set; }
because "an attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type".
Do I need to resort to creating my own custom validator?
OK, found the answer. .NET Framework 4 provides a new CustomValidationAttribute which makes the following possible:
[Required]
[DisplayName("Ideal Delivery Date")]
[CustomValidation(typeof(HeaderViewModel), "ValidateDeliveryDate")]
public DateTime DeliveryDate { get; set; }
public static ValidationResult ValidateDeliveryDate(DateTime deliveryDateToValidate)
{
if (deliveryDateToValidate.Date < DateTime.Today)
{
return new ValidationResult("Delivery Date cannot be in the past.");
}
if (deliveryDateToValidate.Date > DateTime.Today.AddYears(1))
{
return new ValidationResult("Delivery Date must be within the next year.");
}
return ValidationResult.Success;
}
http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.customvalidationattribute%28VS.100%29.aspx
You need to create your own attribute or use a none attribute based validation framework. As the message say, all parameters to any attribute needs to be constant values.
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