1. 在控制器的方法上添加ActionFilter特性

public class HomeController : Controller
{
    [SampleActionFilter]
    public ActionResult AjaxAction()
    {
        return Content("Ajax Action Result");
    }
}

2. 在ActionFilter类中添加以下代码以处理AJAX请求

public class SampleActionFilterAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (filterContext.HttpContext.Request.IsAjaxRequest())
        {
            // Do something for AJAX request
            filterContext.Result = new JsonResult()
            {
                Data = "Error: AJAX request not allowed",
                JsonRequestBehavior = JsonRequestBehavior.AllowGet
            };
        }
        base.OnActionExecuting(filterContext);
    }
}

通过以下代码测试它：

$.ajax({
    type: "GET",
    url: "/home/ajaxaction",
    success: function (data) {
        alert(data);
    },
    error: function (data) {
        alert(data.responseText);
    }
});