给 System.Web.HttpRequest 扩展方法，用来验证是否是 AJAX 请求

直接帖代码：

namespace WebUI
{
    using System;
    using System.Web;

    public static class AjaxRequestExtensions
    {

        public static bool IsAjaxRequest(this HttpRequest request)
        {
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }
            return (request["X-Requested-With"] == "XMLHttpRequest") || ((request.Headers != null) && (request.Headers["X-Requested-With"] == "XMLHttpRequest"));
        }
    }
}

谢谢浏览！