Asp.net webapi enum parameter with default value

Question

I have a controller

   [HttpGet]
    [RoutePrefix(\"api/products/{productId}\")] 
    public HttpResponseMessage Products(int productId,TypeEnum ptype=TypeEnum.C         


        

Answer 1

Defining all your enum parameters as strings and then parsing them everywhere means you have to do this on every single action and you will need to come up with a consistent approach such that all parsing errors conform.

This is a parameter binding issue and should not be dealt with in the controller layer, it should be taken care of in the pipeline. One way to do this is to create a custom filter and add it to your config.

public class ModelStateValidationAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        if (!actionContext.ModelState.IsValid)
        {
            actionContext.Response = 
        }
    }
}

And in your global.asax.cs

...
GlobalConfiguration.Configure(WebApiConfig.Register);
...

public class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        ...
        config.Filters.Add(new ModelStateValidationAttribute());
        ...
    }
}

If you're having trouble with the model state, it's type is a ModelStateDictionary and you simply iterate over it and then it's Errors property contains all the model binding issues. e.g.

modelState = actionContext.ModelState;
modelState.ForEach(x =>
        {
            var state = x.Value;
            if (state.Errors.Any())
            {
                foreach (var error in state.Errors)
                {
                    
                }
            }
        });