TransactionResult.Success不更新我的mutableData（Firebase）

Posted 2023-01-27

我复制了Save Data的代码。

这是这样的：

void addScoreToLeaders(string name, int score ,string 
    key,Dictionary<string,object> childUpdates)    
    reference.Child ("leaders").KeepSynced (true);
    reference.Child ("leaders").RunTransaction(mutableData =>
        List<Dictionary<string,object>> leaders = mutableData.Value as 
                             List<Dictionary<string,object>>;
            if(leaders == null)
                leaders = new List<Dictionary<string,object>>();
             else if(mutableData.ChildrenCount >= MAX_SCORE)
                int minScore = int.MaxValue;
                Dictionary<string,object> minValue = null;
                foreach(var child in leaders)
                    if(!(child is Dictionary<string,object>)) continue;
                    int childScore = (int)((Dictionary<string,object>)child)
                        ["score"];
                    if(childScore < minScore)
                        minScore = childScore;
                        minValue = child;
                    
                
                if(minScore > score)
                    return TransactionResult.Abort ();
                

                leaders.Remove (minValue);              
            

            //Add the new high score
            Dictionary<string ,object> newScoreMap = new 
            Dictionary<string,object> ();
            LeaderBoardEntry entry = new LeaderBoardEntry (name, score);
            newScoreMap = entry.ToDictionary ();
            leaders.Add (newScoreMap);
            mutableData.Value = leaders;
            return TransactionResult.Success (mutableData);
        );
    

好吧，有两件事没有正确发生：

• TransactionResult.Success（mutableData）不会在该位置存储新数据
• 每次第一次调用方法时返回mutableData null

答案

[解决]在检查代码和几次测试尝试后找到了解决方案。

导致问题的代码的第五行（5）是：

List<Dictionary<string,object>> leaders = mutableData.Value as 
                         List<Dictionary<string,object>>; 

用。。。来代替 ：

Dictionary<string,object> leaders = mutableData.Value as 
                         Dictionary<string,object>;

因为mutableData.Value将此实例中包含的数据作为本机类型返回，并且我保存了像Dictionary <.string，object>;这样的数据。