图片:
Content.Headers.ContentType = new MediaTypeHeaderValue("image/png");
视频:
Content.Headers.ContentType = new MediaTypeHeaderValue("video/mp4")
.docx
Content.Headers.ContentType = new MediaTypeHeaderValue("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
原文:https://www.cnblogs.com/yutang-wangweisong/p/14343993.html