Question

我有一个自托管的Web Api控制台应用。我有它提供HTML。在HTML页面中有一个指向图像的链接（图像在编译时是已知的）。我已经尝试并且未能编写控制器方法来检索图像并将其发送到html页面。见下文。我的图像存储为链接资源。

public class ResourceFilesController : ApiController
{
  public HttpResponseMessage Get()
  {

    Stream dataStream =
      System.Reflection.Assembly.GetEntryAssembly().
        GetManifestResourceStream("Properties.Resources.img2");

    HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);

    //Get argumentNull exception on this line
    response.Content = new StreamContent(dataStream);

    return response;
  }
}

Answer 1

dataStream很可能是null ..在这种情况下，webapi没有任何问题。

这是StreamContent构造函数（反编译）

public StreamContent(Stream content, int bufferSize)
{
  if (content == null)
    throw new ArgumentNullException("content");
  if (bufferSize <= 0)
    throw new ArgumentOutOfRangeException("bufferSize");
  this.content = content;
  this.bufferSize = bufferSize;
  if (content.CanSeek)
    this.start = content.Position;
  if (!Logging.On)
    return;
  Logging.Associate(Logging.Http, (object) this, (object) content);
}

因此，除非某些属性设置器抛出ArgumentNull异常或Logging.Associate，否则您将null传递给此构造函数

Answer 2

终于搞清楚了。如果其他人有这个问题，请参阅下面的内容（似乎无法忍受的努力，你必须只是为了提供内容 - 但那个ASP.NET适合你。）

public class PageResourcesController : ApiController
{

    public HttpResponseMessage Get()
    {
        String resourceName = "img2";
        String projectName = "Owin_Test1";

        ResourceManager rm = new ResourceManager(
            projectName + ".Properties.Resources",
            typeof(Properties.Resources).Assembly);
        Object resource = rm.GetObject(resourceName);

        ImageConverter imageConverter = new ImageConverter();

        byte[] resourceByteArray = (byte[])imageConverter.ConvertTo(resource, typeof(byte[]));

        MemoryStream dataStream = new MemoryStream(resourceByteArray);
        HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
        response.Content = new StreamContent(dataStream);
        response.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg");

        return response;
    }
}

使用Web Api将图像返回到网页

2 个答案: