跪求淘宝 API 上传图片的问题


var
  str:string;
  MultiPartFormDataStream: TMsMultiPartFormDataStream;
  ResponseStream: TMemoryStream;
begin
  try
    str:='d:\a.jpg';
    MultiPartFormDataStream := TMsMultiPartFormDataStream.Create;
    ResponseStream := TMemoryStream.Create;
    IdHttp1.Request.ContentType := MultiPartFormDataStream.RequestContentType;
  
    MultiPartFormDataStream.AddFormField('api_key', tbapi_key);
    MultiPartFormDataStream.AddFormField('format',tbformat );
    MultiPartFormDataStream.AddFormField('method','taobao.item.img.upload' );
    MultiPartFormDataStream.AddFormField('num_iid','7109493284');
    MultiPartFormDataStream.AddFormField('timestamp',FormatDateTime('yyyy-mm-dd hh:mm:ss', now) );
    MultiPartFormDataStream.AddFormField('v', tbv);
    //MultiPartFormDataStream.AddFormField('sign',FTaobaoParams.SignParams(tbAppSecret) );
    MultiPartFormDataStream.AddFile('image', str,'multipart/form-data');
    MultiPartFormDataStream.PrepareStreamForDispatch;
    MultiPartFormDataStream.Position := 0;    IdHTTP1.Post('http://gw.api.taobao.com/router/rest', MultiPartFormDataStream, ResponseStream);
    ResponseStream.SaveToFile('d:\a.txt');
    Memo1.Lines.LoadFromFile('d:\a.txt');
  finally
    FStrings.free;
  end;
上面的这段代码，提交到top api服务器之后，就报错，报缺失方法