将List值添加到字典中

Question

我正在尝试填充一个字典,其中唯一的主题值具有应与其匹配的各种代码值.

CODE    SUBJECT

7DIM-062  Recruitment and Selection

7DIM-063    Recruitment and Selection

7DIM-064    Recruitment and Selection

7DIM-065    Recruitment and Selection

7DIM-066    Recruitment and Selection

7DIM-067    Recruitment and Selection

7DIM-068    Recruitment and Selection

所以我想要的只是将Reqruitment和Selection作为唯一键添加到Dictionary中,然后将所有相应的代码添加到List中.我该怎么做呢？

Dictionary<string, List<string>> dict = new Dictionary<string,List<string>>();

这是我的疑问

OleDbDataReader dbReader = cmd.ExecuteReader();
while (dbReader.Read())
{
    string code = (string)dbReader["CODE"];
    string subject = (string)dbReader["SUBJECT"];
    //???? this is the point where I would want to add the values
    dict.Add(subject, new List<string>().Add(code);

Answer 1

首先检查你的字典是否已经有密钥,如果没有List初始化则添加新密钥.

if (!dict.ContainsKey(subject))
{
    dict[subject] = new List<string>();    
}

dict[subject].Add(code);