清单和清除方法存在问题：

Dictionary<string, List<DisplayAllQuestionsTable>> tPages= new Dictionary<string, List<DisplayAllQuestionsTable>>();;
List<DisplayAllQuestionsTable> threadsByTopic = new List<DisplayAllQuestionsTable>();
int tPage=0;
        foreach (var topicKeys in postsByTopic)
        {

               if (topicKeys.Key == subTopic)
                {
                    foreach (var item in postsByTopic[topicKeys.Key])
                    {
                        questionNumber++;
                        maximumTopicPages++;
                        threadsByTopic.Add(item);//Adds All DisplayAllTables objects
                        //if there are 20 add a button.
                        if (maximumTopicPages == 20)
                        {
                            tPages.Add(tPage.ToString(), threadsByTopic);//The threadsByTopic clears everytime i call threadsByTopic.clear()

                            threadsByTopic.Clear();
                            tPage++;

                    }
                }