core基础常用的部分HttpContext'常用操作

{
// IConfiguration Configuration 得注入，二级节点的访问，用冒号 .GetSection("AppSettings:" + name)
   Configuration.GetSection("").Value; 
}

// 先下载session的扩展nuget包 Microsoft.aspnetcore.http.extensions
services.AddSession(); //写在 ConfigureServices中； 
app.UseSession(); //写在 Configure中
HttpContextHelper.Current.Session.GetString("pwdqrcodekey");

public class LoginFltAttribute : Attribute, IActionFilter
{
/// <summary>
/// 执行后
/// </summary>
/// <param name="context"></param>
public void OnActionExecuted(ActionExecutedContext context)
{}

/// <summary>
/// 执行前
/// </summary>
/// <param name="context"></param>
public void OnActionExecuting(ActionExecutingContext context)
{}
}

// string actionName = filterContext.ActionDescriptor.ActionName; //MVC5写法
   string actionName = filterContext.Controller.GetType().Name; //Core写法

filterContext.Result = new ViewResult { ViewName = "error", ViewData = new ViewDataDictionary<Return_Msg>(msg) }; //MVC5写法

/*ViewDataDictionary实例化不了，多用快速监视，使用viewData，来构造他，就可以使用他了*/
ViewDataDictionary<Return_Msg> viewdata = new ViewDataDictionary<Return_Msg>(((Controller)filterContext.Controller).ViewData, msg);
filterContext.Result = new ViewResult() { ViewName = "error", ViewData = viewdata }; //Core的写法

filterContext.Controller.ViewBag.RightBtnView //MVC5写法
Controller controller = filterContext.Controller as Controller;
controller.ViewBag.RightBtnView = btnView; //Core写法

int zbid = Convert.ToInt32(filterContext.ActionParameters[pDesc.ParameterName]); //MV5的写法
int zbid= filterContext.ActionArguments[pDesc.Name].ToString(); //Core写法
filterContext.ActionDescriptor.Parameters。 Ilist<ParameterDescriptor>//集合形式的存放
filterContext.ActionDescriptor.Parameters[0].Name //获得第一个参数的名称，只能拿到参数名称，不能拿到key对应的value值
filterContext.ActionArguments//字典形式的参数列表，可以拿到key与value值，更加灵活

List<string> arrQueryKeys = filterContext.HttpContext.Request.QueryString.AllKeys.ToList(); //MV5写法
List<string> arrQueryKeys = filterContext.HttpContext.Request.Form.Keys.ToList(); //前端Form表单参数的集合
KeyValuePair<string, Microsoft.Extensions.Primitives.StringValues>[] kk= filterContext.HttpContext.Request.Query.ToArray(); //地址栏的参数列表，这里转换成 数组，Core写法

int zbid= Convert.ToInt32(filterContext.HttpContext.Request.Params[keyName]); //MV5的写法
int zbid = Convert.ToInt32(filterContext.HttpContext.Request.Form.FirstOrDefault(i => i.Key == keyName).Value);

filterContext.HttpContext.Request.UrlReferrer.OriginalString; //MVC5判断请求的头中有没有“Referer”是否为空
filterContext.HttpContext.Request.Headers["Referer"]; //Core

filterContext.HttpContext.Request.IsAjaxRequest()//MC5
判断是否是Ajax请求 判断Head头部是否有 “X-Requested-With: XMLHttpRequest”，有=Ajax请求
public static bool IsAjaxRequest(this HttpRequest request)
{
   bool result = false;
   var xreq = request.Headers.ContainsKey("x-requested-with");
   if (xreq)
   result = request.Headers["x-requested-with"] == "XMLHttpRequest";
   return result;
}

protected virtual T CreateService<T>()
{
   // typeof(T) ==>接口名
   return (T)this.HttpContext.RequestServices.GetService(typeof(T));
}