google api v3 C# cant read file permissions details (filePermissions.Permissions[i].EmailAddress) -

my issue can't read email or user name each file permission

i need read have permission on each files in google drive api v3

   var service = new driveservice(new baseclientservice.initializer()         {             httpclientinitializer = credential,             applicationname = applicationname,         });           // define parameters of request         filesresource.listrequest listrequest = service.files.list();         //*///////////////// getdataitem share file me          listrequest.q = "(sharedwithme = true)";         listrequest.fields = "*";         var results = listrequest.execute();           //*////////////end  getdataitem share file me           listrequest.pagesize = 10;         listrequest.fields = "nextpagetoken, files(id,name,viewedbyme)";          // list files.         ilist<google.apis.drive.v3.data.file> files = listrequest.execute()     .files;         console.writeline("files:");         if (files != null && files.count > 0)         {             foreach (var file in files)              {                  response.write("<br>file name = " + file.name.tostring() + " *file id  = * " + file.id.tostring() + "<br>");                  try                 {                     response.write("createdtime = " + file.createdtime.tostring() + "<br>");                 }                 catch (exception ex)                 {                     response.write(ex.message.tostring() + " ex && <br> ");                 }                  try                 {                     permissionlist filepermissions = service.permissions.list(file.id.tostring()).execute();                       int permissionc = filepermissions.permissions.count;                      response.write("count:" + permissionc.tostring() + " // ");                      (int = 1; < permissionc; i++)                     {                         string permissionid = filepermissions.permissions[i].id.tostring();                         var ff = service.permissions.get(file.id.tostring(), permissionid);                          response.write("permissionid  = " + permissionid + "<br> ");                         response.write("kind  = " + filepermissions.kind.tostring() + "<br> ");                         //response.write("etag  = " + filepermissions.permissions[i].etag.tostring() + "<br> ");                         response.write("role  = " + filepermissions.permissions[i].role.tostring() + "<br> ");                         var email = "";                             if (filepermissions.permissions[i].emailaddress != null)                         { email = filepermissions.permissions[i].emailaddress.tostring(); }                          response.write("emailaddress  = " + email + "<br> ");                         response.write("type  = " + filepermissions.permissions[i].type.tostring() + "<br> ");                          if (filepermissions.permissions[i].displayname != null)                         {                             response.write("<br> name : " + filepermissions.permissions[i].displayname.tostring() + "** ");                          }                     }                  }                 catch (exception er)                  {                     response.write(er.message.tostring() + " err && <br> ");                  }