c# - C# WCF JSON WebService 返回 mime 类型的图像/png

Question

我正在使用 JSON 格式运行 WCF Web 服务，如下所示。我的问题是响应格式是 Alowas Json 或 XML，但对于 GetImage，我想将图像返回为 mime-type image-png。知道如何在 WCF 中执行此操作吗？提前致谢。

[ServiceContract]
public interface IEditor
{
    [OperationContract]
    [WebInvoke(Method = "GET", UriTemplate = "/GetImage", RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped)]
    byte[] GetImage();

[OperationContract]
[WebInvoke(Method = "GET", UriTemplate = "/GetBounds", RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped)]
void GetBounds(out Rectangle bounds, out Point[] viewport);

Answer 1

1. 利用WebOperationContext.Current

2. 返回Stream

你的方法应该是这样的

[OperationContract]
[WebInvoke(Method = "GET", UriTemplate = "/GetImage", RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped)]
public Stream GetImage()
{
    var m = new MemoryStream();
    //Fill m

    // very important!!! otherwise the client will receive content-length:0
    m.Position = 0;

    WebOperationContext.Current.OutgoingResponse.ContentType = "image/png";
    WebOperationContext.Current.OutgoingResponse.ContentLength = m.Length;
    return m;
}