public async Task FileUploadDB(string dropboxpath, string filename, string filepath, FileStream fs, DropNetClient client)
        {
            //client = new DropNetClient(apiKey, appSecret, GetUserLoginDB(tokendb), GetUserLoginDB(secretdb));

            //******************NORMALASYCNMETHODE
            /*client.UploadFileAsync(dropboxpath, filename, File.ReadAllBytes(filepath),
                (response) =>
                {
                    if(response != null)
                    {
                        string t = response.Bytes.ToString();

                        byte[] bytes = new byte[t.Length * sizeof(char)];
                        System.Buffer.BlockCopy(t.ToCharArray(), 0, bytes, 0, bytes.Length);
                    }         
                },
                (error) =>
                {
                    MessageBox.Show("error uploading");
                });*/
            //***************TASKMETHODE

            try
            {
                byte[] DataArray = FileToByteArray(filepath);

                //using (fs = new FileStream(filepath, FileMode.Open))
                //{
                //    await client.UploadFileTask(dropboxpath, filename, fs);   //Methode mit FileStream funktioniert nicht :/
                //}

                await client.UploadFileTask(dropboxpath, filename, DataArray);  //Methode mit byte array funktioniert gut
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }