问如何用封面照片创建facebook新活动

EN

FacebookClient facebookClient = new FacebookClient(accessToken);
Dictionary<string, object> createEventParameters = new Dictionary<string, object>();
createEventParameters.Add("name", "test");
createEventParameters.Add("start_time", DateTime.Now.ToUniversalTime().ToString("yyyyMMdd"));
createEventParameters.Add("end_time", DateTime.Now.AddDays(2).AddHours(4).ToUniversalTime().ToString("yyyyMMdd"));
createEventParameters.Add("owner", "me");
createEventParameters.Add("description", "description");
JsonObject venueParameters = new JsonObject();
venueParameters.Add("street", "test");
venueParameters.Add("city", "test");
venueParameters.Add("state", "test");
venueParameters.Add("zip", "0000");
venueParameters.Add("country", "test");
venueParameters.Add("latitude", "100.0");
venueParameters.Add("longitude", "100.0");
createEventParameters.Add("venue", venueParameters);
createEventParameters.Add("privacy", "OPEN");
createEventParameters.Add("location", "test");
FacebookMediaObject logo = new FacebookMediaObject(){
   ContentType = "image/jpeg",
   FileName = @"J:\logo.jpg"
};
logo.SetValue(System.IO.File.ReadAllBytes(logo.FileName));
createEventParameters.Add("picture", logo);
JsonObject result = facebookClient.Post("/my_page_Id/events", createEventParameters) as JsonObject;

createEventParameters.Add("cover_url", "photo_url");