c# - 将多个对象作为值添加到字典中的键

Question

我的任务是读取 CSV 文件并将文件的内容放入字典中。

问题是读入的每一行都有一个已经存在于字典中的键。我被告知将读入的每一行作为值(从类对象)添加到与该行相关的键中，即帐户。

因此文件示例在每一行中看起来像这样，大约有 10 个帐户，但有 8,000 行:

帐户 1、值 1、值 2、值 3

帐户 1、值 1、值 2、值 3

所以我被要求做的是，当已经存在一个不同的键时，我需要将对象(读入的每一行)添加到该值中。

但是当我被要求对一个对象执行此操作时，这真的让我感到困惑。我理解字典的方式是，如果键/值对是这样的 (string, int):

键 1, 5

键 1, 10

当我将第二个值添加到不同的键时，它将如下所示: 键 1, 15

当谈到使用像 int 这样的简单值时，我完全可以理解这一点。

但是如果我使用类作为我的值:

    public class DataRecord
    {
        public string account;
        public int open;
        public int buy;
        public int sell;
        public double settleMM;
        public string underlying;
        public string symbol;
    }

到目前为止，这是我的应用程序:

    static void Main(string[] args)
    {
        double dParseSettleMM;
        int iParseOpen;
        int iParseBuy;
        int iParseSell;
        string sUnderlyingControl = string.Empty;
        string sUnderlying = string.Empty;
        string sAccount = string.Empty;
        string sAccountControl = string.Empty;

        var path = @"C:\Users\jhochbau\documents\visual studio 2015\Projects\CsvReader\CSVReaderList\Position_2016_02_25.0415.csv";

        Dictionary<string, DataRecord> vSummaryResults = new Dictionary<string, DataRecord>();

        //Sets up control to switch between sorted lists.
        Console.WriteLine("Enter 1 to sort by Account, 2 to sort by Underlying, 3 to sort by Account and Underlying");
        string control = Console.ReadLine();

        //open reader
        StreamReader r = new StreamReader(path);
        StreamWriter vWriteFile = new StreamWriter("Positions2.csv");

        //Consume first line
        r.ReadLine();

        //While loop to populate List with record Objects
        while (!r.EndOfStream)
        {

            DataRecord records = new DataRecord();
            var line = r.ReadLine();
            var values = line.Split(',');

            //Need to add into dictionary...
            if (vSummaryResults.ContainsKey(records.account))
            {
                vSummaryResults[records.account].open += records.open;
            }
            else
            {
                vSummaryResults.Add(records.account, records);
            }
        }

    }

编辑:这是我的具体问题。有人告诉我这段代码已经可以工作了，我想了解的是工作方式和原因，并试图将其形象化以理解它。

当我将该类添加到字典时，该类中的每个字段到底发生了什么？用作值的我的 DataRecord 类是否只有这些字段的多个实例？

Answer 1

使您的字典值成为 DataRecords 的列表(或其他集合)。

Dictionary<string, List<DataRecord>> vSummaryResults = new Dictionary<string, List<DataRecord>>();

然后您可以将在执行过程中发现的任何新值添加到该列表。

选项 1:我继续修改您的代码来执行此操作。

static void Main(string[] args)
{
    double dParseSettleMM;
    int iParseOpen;
    int iParseBuy;
    int iParseSell;
    string sUnderlyingControl = string.Empty;
    string sUnderlying = string.Empty;
    string sAccount = string.Empty;
    string sAccountControl = string.Empty;

    var path = @"C:\Users\jhochbau\documents\visual studio 2015\Projects\CsvReader\CSVReaderList\Position_2016_02_25.0415.csv";

    Dictionary<string, List<DataRecord>> vSummaryResults = new Dictionary<string, List<DataRecord>>();

    //Sets up control to switch between sorted lists.
    Console.WriteLine("Enter 1 to sort by Account, 2 to sort by Underlying, 3 to sort by Account and Underlying");
    string control = Console.ReadLine();

    //open reader
    StreamReader r = new StreamReader(path);
    StreamWriter vWriteFile = new StreamWriter("Positions2.csv");

    //Consume first line
    r.ReadLine();

    //While loop to populate List with record Objects
    while (!r.EndOfStream)
    {

        DataRecord records = new DataRecord();
        var line = r.ReadLine();
        var values = line.Split(',');

        //Need to add into dictionary...
        if (vSummaryResults.ContainsKey(records.account))
        {
            vSummaryResults[records.account].Add(record);
        }
        else
        {
            vSummaryResults.Add(records.account, new List<DataRecord>());
            vSummaryResults[records.account].Add(record);
        }
    }

}

选项 2:因为您不能使用选项 1。这将序列化每条记录并将其附加到键的值。然后你可以用'，'拆分它并反序列化它。上面的方法比较好，但是如果你不能使用它，那么这个应该可以。

static void Main(string[] args)
{
    double dParseSettleMM;
    int iParseOpen;
    int iParseBuy;
    int iParseSell;
    string sUnderlyingControl = string.Empty;
    string sUnderlying = string.Empty;
    string sAccount = string.Empty;
    string sAccountControl = string.Empty;

    var path = @"C:\Users\jhochbau\documents\visual studio 2015\Projects\CsvReader\CSVReaderList\Position_2016_02_25.0415.csv";

    Dictionary<string, string> vSummaryResults = new Dictionary<string, string>();

    //Sets up control to switch between sorted lists.
    Console.WriteLine("Enter 1 to sort by Account, 2 to sort by Underlying, 3 to sort by Account and Underlying");
    string control = Console.ReadLine();

    //open reader
    StreamReader r = new StreamReader(path);
    StreamWriter vWriteFile = new StreamWriter("Positions2.csv");

    //Consume first line
    r.ReadLine();

    //While loop to populate List with record Objects
    var serializer = new JavaScriptSerializer();
    while (!r.EndOfStream)
    {

        DataRecord records = new DataRecord();
        var line = r.ReadLine();
        var values = line.Split(',');

        //Need to add into dictionary...
        if (vSummaryResults.ContainsKey(records.account))
        {
            vSummaryResults[records.account] += "," + serializer.Serialize(record);
        }
        else
        {
            vSummaryResults.Add(records.account, serializer.Serialize(record));
        }
    }

}