Is there any attribute relating to AJAX to be set for ASP.NET MVC controller actions?

Question

I want to use partial views with AJAX calls in ASP.NET MVC, and this is the first time I\'m using it. I just searched to see if there is anything special I should know befor

Answer 1

I don't think there is built in attribute for ajax, but you can create your own AjaxOnly filter like this:

public class AjaxOnlyAttribute : ActionMethodSelectorAttribute 
{
    public override bool IsValidForRequest(ControllerContext controllerContext, System.Reflection.MethodInfo methodInfo)
    {
        return controllerContext.RequestContext.HttpContext.Request.IsAjaxRequest();
    }
}

And decorate your action methods like this:

[AjaxOnly]
public ActionResult AjaxMethod()
{
   
}

See Also: ASP.NET MVC Action Filter – Ajax Only Attribute for another way of implementing this

Answer 2

A spinoff of Muhammad's answer letting you specify that it mustn't be an ajax request as well:

using System.Web.Mvc;
public class AjaxAttribute : ActionMethodSelectorAttribute
{
    public bool ajax { get; set; }
    public AjaxAttribute() { ajax = true; }
    public AjaxAttribute(bool a) { ajax = a; }
    public override bool IsValidForRequest(ControllerContext controllerContext, System.Reflection.MethodInfo methodInfo)
    {
        return ajax == controllerContext.HttpContext.Request.IsAjaxRequest();
    }
}

This lets you do things like...

[Ajax]
public PartialViewResult AjaxUpdatingPage() {
    return PartialView();
}

[Ajax(false)]
public ViewResult NotAjaxUpdatingPage() {
    return View();
}

Answer 3

my solution follows the [ChildActionOnly] implementation:

public class AjaxOnlyAttribute : FilterAttribute, IAuthorizationFilter
{
    public void OnAuthorization(AuthorizationContext filterContext)
    {
        if (filterContext == null)
            throw new ArgumentNullException("filterContext");
        if (!filterContext.HttpContext.Request.IsAjaxRequest())
            throw new InvalidOperationException(string.Format(
                CultureInfo.CurrentCulture, 
                "The action '{0}' is accessible only by an ajax request.", 
                filterContext.ActionDescriptor.ActionName
            ));
    }
}

Answer 4

ASP.NET MVC provides an extension method to check if an Request is an Ajax Request. You can use it to decide if you want to return a partial view or json result instead of a normal view.

if (Request.IsAjaxRequest())
{
    return PartialView("name");
}
return View();

To limit an action method to Ajax calls only you can write a custom attribute. In case of a normal request this filter will return a 404 not found http exception.

[AttributeUsage(AttributeTargets.Method)]
public class AjaxOnlyAttribute : ActionFilterAttribute
{
     public override void OnActionExecuting(ActionExecutingContext filterContext)
     {
        if (!filterContext.HttpContext.Request.IsAjaxRequest())
        {
            filterContext.HttpContext.Response.StatusCode = 404;
            filterContext.Result = new HttpNotFoundResult();
        }
        else
        {
            base.OnActionExecuting(filterContext);
        }
     }
}

you can use it like that:

[AjaxOnly]
public ActionResult Index() {
    // do something awesome
}

Answer 5

For those looking for a .NET Core solution it's a little bit more involved, as IsAjaxRequest() is no longer available.

Below is the code I've used in production on several projects to great effect.

public class AjaxOnlyAttribute : ActionMethodSelectorAttribute
{
  public override bool IsValidForRequest(RouteContext routeContext, ActionDescriptor actionDescriptor)
  {
    if(routeContext.HttpContext.Request.Headers != null &&
      routeContext.HttpContext.Request.Headers.ContainsKey("X-Requested-With") &&
      routeContext.HttpContext.Request.Headers.TryGetValue("X-Requested-With", out StringValues requestedWithHeader))
    {
      if(requestedWithHeader.Contains("XMLHttpRequest"))
      {
        return true;
      }
    }

    return false;
  }
}

Answer 6

There is an [AjaxOnly] attribute provided in the ASP.NET MVC 3 Futures collection. It's a part of the official ASP.NET MVC Codeplex site that provides features before they are officially included in a future version of ASP.NET MVC.

You can download it here. To use it, add a reference to the Microsoft.Web.Mvc assembly included in the release package.

There is an explanation of the attribute on this page, along with all the other great features you can use.