private void btnLogin_Click(object sender, RoutedEventArgs e)
{
List<string> scope = new List<string> {
"publish_feed",
"publish_blog",
"publish_share",
"read_user_album",
"read_user_status",
"read_user_photo",
"read_user_comment",
"read_user_status",
"publish_comment",
"read_user_share",
"create_album",
"status_update",
"photo_upload" };
api.Login(this,scope, renren_LoginCompletedHandler);
}