Question

I am using Data Annotations to validate my Model in ASP.NET MVC. This works well for action methods that has complex parameters e.g,

public class Params  
{  
    [Required] string Param1 {get; set;}   
    [StringLength(50)] string Param2 {get; set;}  
}


ActionResult MyAction(Params params)  
{  
   If(ModeState.IsValid)  
   {  
      // Do Something  
   }  
}

What if I want to pass a single string to an Action Method (like below). Is there a way to use Data Annotations or will I have to wrap the string into a class?

ActionResult MyAction(string param1, string param2)  
{  
   If(ModeState.IsValid)  
   {  
     // Do Something  
   }  
}  

Answer 1

I don’t believe there is a Data Annotations method to what you are proposing. However, if you want your validation to happen before the action method is invoked, consider adding a custom model binder attribute to the parameter and specify a specific model binder you want to use.

Example:

public ActionResult MyAction [ModelBinder(typeof(StringBinder)] string param1, [ModelBinder(typeof(StringBinder2)] string param2)
{
  .........
}