最近在循环中给字典中的列表进行添加操作时，发现直接通过一个列表添加是不可行的，需要创建新的列表才可以，还是比较好理解的，如下所示：

Dictionary<string, List<string>> myDic = new Dictionary<string, List<string>>();
myDic.Add(newKey, new List<string>(existingList));

示例如下：

Dictionary<string, List<String>> map = new Dictionary<string, List<String>>();
    
    // create list one and store values
    List<string> valSetOne = new List<string>();
    valSetOne.Add("Apple");
    valSetOne.Add("Aeroplane");
    
    // create list two and store values
    List<String> valSetTwo = new List<String>();
    valSetTwo.Add("Bat");
    valSetTwo.Add("Banana");
    
    // create list three and store values
    List<String> valSetThree = new List<String>();
    valSetThree.Add("Cat");
    valSetThree.Add("Car");
    
    // add values into map
    map.Add("A", valSetOne);
    map.Add("B", valSetTwo);
    map.Add("C", valSetThree);
  
    // iterate and display values
    foreach(KeyValuePair<string, List<string>> kvp in map){
      foreach(string value in kvp.Value){
         Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, value);
      }

参考博客：

https://stackoverflow.com/questions/17887407/dictionary-with-list-of-strings-as-value

https://gist.github.com/ishu3101/4a5846860fc268d0fc7323171e2d92ff

https://stackoverflow.com/questions/14991688/adding-items-to-a-list-in-a-dictionary/14991876

https://stackoverflow.com/questions/17108399/dictionaryint-liststring