public string GetVMVHDs(string vmid)
        {
            try
            {
                List <AjaxVMVHDs> vhds = new List <AjaxVMVHDs>();

                using (MyPowerShell ps = new MyPowerShell())
                {
                    ps.GetVMVHDs(vmid);
                    IEnumerable <PSObject> result = ps.Invoke();

                    foreach (PSObject VHD in result)
                    {
                        Dictionary <string, object> properties = CommonCAS.GetPSObjectProperties(VHD);
                        vhds.Add(new AjaxVMVHDs()
                        {
                            Name  = properties["Name"].ToString(),
                            VHDID = properties["VHDID"].ToString(),
                            Size  = properties["Size"].ToString(),
                        });
                    }
                }


                return(new JavaScriptSerializer().Serialize(vhds));
            }
            catch (Exception exc)
            {
                return(new JsonException(exc).ToString());
            }
        }