如何实例化 HttpPostedFile

问题描述

我正在尝试与一个我无法控制的系统进行通信，但是它的一个方法接受 HttpPostedFile 在我的代码中我有一个字节数组.有没有人有实例化 HttpPostedFile 的例子，因为我知道它的构造函数是内部的?

I'm trying to communicate with a system which I have no control over, however one of its methods takes in a HttpPostedFile were in my code I have a byte array. Does anybody have an example of instantiating a HttpPostedFile as I know its constructor is internal?

我发现最好的是使用反射创建 HttpPostedFile 实例 使用反射，但是它们被引导到另一个我无法接受的方向，因为我无法修改第三方系统方法签名.

The best I've found is Creating an instance of HttpPostedFile with Reflection which uses reflection, however they were steered into another direction which I can't take because I am unable to modify the third party systems method signature.

推荐答案

这真的是很黑的代码，但以下似乎对我有用:

This is really really hacky code, but the following seems to work for me:

public HttpPostedFile ConstructHttpPostedFile(byte[] data, string filename, string contentType) {
  // Get the System.Web assembly reference
  Assembly systemWebAssembly = typeof (HttpPostedFileBase).Assembly;
  // Get the types of the two internal types we need
  Type typeHttpRawUploadedContent = systemWebAssembly.GetType("System.Web.HttpRawUploadedContent");
  Type typeHttpInputStream = systemWebAssembly.GetType("System.Web.HttpInputStream");

  // Prepare the signatures of the constructors we want.
  Type[] uploadedParams = { typeof(int), typeof(int) };
  Type[] streamParams = {typeHttpRawUploadedContent, typeof (int), typeof (int)};
  Type[] parameters = { typeof(string), typeof(string), typeHttpInputStream };

  // Create an HttpRawUploadedContent instance
  object uploadedContent = typeHttpRawUploadedContent
    .GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance, null, uploadedParams, null)
    .Invoke(new object[]{data.Length, data.Length});

  // Call the AddBytes method
  typeHttpRawUploadedContent
    .GetMethod("AddBytes", BindingFlags.NonPublic | BindingFlags.Instance)
    .Invoke(uploadedContent, new object[] {data, 0, data.Length});

  // This is necessary if you will be using the returned content (ie to Save)
  typeHttpRawUploadedContent
    .GetMethod("DoneAddingBytes", BindingFlags.NonPublic | BindingFlags.Instance)
    .Invoke(uploadedContent, null);

  // Create an HttpInputStream instance
  object stream = (Stream)typeHttpInputStream
    .GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance, null, streamParams, null)
    .Invoke(new object[] {uploadedContent, 0, data.Length});

  // Create an HttpPostedFile instance
  HttpPostedFile postedFile = (HttpPostedFile)typeof(HttpPostedFile)
    .GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance, null, parameters, null)
    .Invoke(new object[] {filename, contentType, stream});

  return postedFile;
}

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