vk API. How to upload photos in a private message?

Question

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I'm trying, I mean, upload a photo to the VK dialog, I use the Vk.Net library for C # for this

var imageFile = "C:\\имя_картинки.jpeg"

              var uploadServer = api.Photo.GetMessagesUploadServer(); //Получаем ссылку на сервер для загрузок
              var uploadServerUri = uploadServer.UploadUrl;
              var uploader = new WebClient();
              var uploadResponseInBytes = uploader.UploadFile(uploadServerUri, imageFile); // Загружаем фото на сервер
              var uploadResponseInString = Encoding.UTF8.GetString(uploadResponseInBytes); 

              var jsonObject = (JObject)JsonConvert.DeserializeObject(uploadResponseInString);
              var photoParameter = jsonObject["photo"].ToString(); // вынимаем photo из ответа (исп. Newtonsoft.json)

Here is the photo returned:

[{"photo":"49c64fbb0a:w","sizes":,"kid":"92e5a11b70f880ac622c7fea7f5aba7c","debug":"xswmwxwywzwwwowpwqwrw"}]

Next, I save it:

var photo = api.Photo.SaveMessagesPhoto(photoParameter);

Here is the error it returns:

error: {
error_code: 118,
error_msg: 'Invalid server',
request_params: [{
key: 'oauth',
value: '1'
}, {
key: 'method',
value: 'photos.saveMessagesPhoto'
}, {
key: 'photo',
value: '[{"photo":"49c64fbb0a:w","sizes":[["s","629526621","21260","6Jkf9T9YZjE",58,75],["m","629526621" ,"21261","4YmH_tNjSBc",100,130],["x","629526621","21262","LvxGnkaZwL8",464,604],["y","629526621","21263","O21xjup4jp4",620,807 ],["z","629526621","21264","v2kvn2V540o",830,1080],["w","629526621","21265","v76d9glIcJo",922,1200],["o" ,"629526621","21266","ihP89qpXY1E",130,169],["p","629526621","21267","i1SUBQRgNtM",200,260],["q","629526621","21268","
{
key: 'v',
value: '5.40'
}]
}

How to be? I have already re-read a bunch of guides, googled all the possible formulations of my problem, no one has ever met anything like this.

Answer 1

...

error_code: 118,
error_msg: 'Invalid server',

...
Invalid server.
Returns the address of the server to upload the photo to...
Saves the photo after a successful upload to the URI
Might be a bug here
I guess it should be like this
var uploadServerUri = uploadServer.upload_url;