c#之如何向 Request.Form 集合添加值

我需要向 Request.Form 集合添加值，但我不明白如何使用指定的表单值初始化 HttpRequest 实例。我试图重写 Controller 中的 Initialize 方法并像这样初始化 HttpRequest:

protected override void Initialize(System.Web.Routing.RequestContext requestContext) 
{ 
   var requestField = typeof (HttpRequestWrapper).GetField("_httpRequest", BindingFlags.NonPublic | 
                                                                               BindingFlags.Instance); 
   var responseField = typeof(HttpResponseWrapper).GetField("_httpResponse", BindingFlags.NonPublic | BindingFlags.Instance); 
 
 
   var req = (HttpRequest) requestField.GetValue(requestContext.HttpContext.Request); 
   var res = (HttpResponse)responseField.GetValue(requestContext.HttpContext.Response); 
//**************** HERE I TRY TO INITIZLIZE FORM COLLECTION WITH MY VALUE 'additional_form_value' but nothing   
   var newReq = new HttpRequest(null, req.Url.ToString(), "?additional_form_value=test"); 
   newReq.RequestType = "POST"; 
//*************** 
 
 
   var r = new RequestContext(new HttpContextWrapper(new HttpContext(newReq, res)), requestContext.RouteData); 
 
 
   base.Initialize(r); 
} 

有什么方法可以将新项目添加到 Request.Form 集合中？

编辑:

当我尝试这种方法时出现异常(对象引用未设置为对象的实例。):

NameValueCollection oQuery = requestContext.HttpContext.Request.QueryString; 
oQuery = (NameValueCollection)requestContext.HttpContext.Request.GetType().GetField("_form", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(requestContext.HttpContext.Request); //exception here 
PropertyInfo oReadable = oQuery.GetType().GetProperty("IsReadOnly", BindingFlags.NonPublic | BindingFlags.Instance); 
oReadable.SetValue(oQuery, false, null); 
oQuery["foo"] = "bar"; 
oReadable.SetValue(oQuery, true, null); 

请您参考如下方法:

在将其添加到帖子之前建立您的数据。

您需要将数据添加到请求的流中，这样应该可行:

using(HttpWebRequest myHttpRequest = (HttpWebRequest)WebRequest.Create(myUrl) 
{ 
   byte[] bytes = Encoding.UTF8.GetBytes(myFormData); 
   Stream requestStream = null; 
   try 
   { 
      myHttpRequest.ContentLength = bytes.Length; 
      requestStream = myHttpRequest.GetRequestStream(); 
      requestStream.Write(bytes, 0, bytes.Length); 
   } 
} 

您可能需要更改编码类型，但希望这对您有所帮助，除非我完全弄错了您的问题。