Question

i have an action and want to do some simple check on param

ActionResult Test([Range(0,10)] int i)
{
  // ModelState.IsValid is always true, i want it to be false if i > 10 or i < 0
}

anyway to fix this or work around it or any alternatives provided by MVC?

Answer 1

I thought of just checking the data annotation attribute definition before giving you some alternate options. I surprised to see that the AttributeUsage is defined in such that you can apply to the method parameters as well and unfortunately it not worked as i tried myself. Though I’m not sure why they have allowed this parameter to method parameters (I see it’s valid but not working)

Regarding alternate options you could try this,

public ActionResult Test(int i)
{
   var rangeAttr = new RangeAttribute(0, 10);

   if(!rangeAttr.IsValid(i))
     ModelState.AddModelError(i.ToString(), rangeAttr.FormatErrorMessage("i"));       
}