最后一行代码就是错误所在。因为这是一个异步调用,所以您必须等待它。然而,这意味着该代码所在的方法需要标记为async。您没有显示该代码,因此不确定这是否在主方法中。但最终,它应该是这样的:
public static async Task Main(params object[] parameters)
{
var client = new RestClient(url);
var request = new RestRequest("/webapi/entry.cgi", Method.Post);
request.AddHeader("Cookie", "did="+_did+"; id="+_sid);
request.AddParameter("api", "SYNO.FileStation.Upload", ParameterType.RequestBody);
request.AddParameter("version", "3", ParameterType.RequestBody);
request.AddParameter("method", "upload", ParameterType.RequestBody);
request.AddParameter("path", "my_path", ParameterType.RequestBody);
request.AddParameter("create_parents", "False", ParameterType.RequestBody);
request.AddFile("filename", filename, "application/octet-stream");
var response = await client.ExecutePostAsync(request);
}