.net mvc 2 validation: summing up values of several attributes
I am using .NET 4 MVC 2 in my project. I basically have two classes, which I use for my validation. Class A is my (main) model, class B is an composite attribute which class A may have. The code looks like the following:
[Bind(Exclude = "A_ID")]
public class A_Validation
{
[Required(ErrorMessage = "something is missing")]
public string title { get; set; }
// some more attributes ...
public B b { get; set; }
}
All my validation based on class A is working very well. But now I want to validate the composite attribute B, which looks like the following.
[Bind(Exclude = "B_ID")]
public class B_Validation
{
[Required(ErrorMessage = "missing")]
[Range(1, 210, ErrorMessage = "range between 1 and 210")]
public int first { get; set; }
[Required(ErrorMessage = "missing")]
[Range(1, 210, ErrorMessage = "range between 1 and 210")]
public int second { get; set; }
[Required(ErrorMessage = "missing")]
[Range(1, 210, ErrorMessage = "range between 1 and 210")]
public int third { get; set; }
}
I am able to check the ranges of B's three attributes first,second and third. What I additionally want is to check if the sum of all three attributes first,second and third is below a certain threshold.
Any ideas how to proceed?
I think ViewModels might help, but i have no experience in using them.
Have you tried writing a custom validation attribute:
public class SumBelowAttribute : ValidationAttribute
{
private readonly int _max;
public SumBelowAttribute(int max)
{
_max = max;
}
public override bool IsValid(object value)
{
var b = value as B_Validation;
if (b != null)
{
return b.first + b.second + b.third < _max;
}
return base.IsValid(value);
}
}
and then decorate the B property with this attribute:
[SumBelow(123)]
public B b { get; set; }