C# 联接datatable和collection并在LINQ C中返回一个列表#

我有一个数据表

**Code    value   stdcode   desc****
  code1   value1  abcd12     abcjkdh
  code2   value2  cdfg34     sdfiuysd
   .       .       .          .
   .       .       .           .

我有一张单子

**stdcode   desc**
  abcd12    sdfsd
  fhry67    uisydif

我想在stdcode上使用linq连接这两个

请提供解决方案

我已经尝试将datatable转换为list，并尝试将两者结合起来

 List<stdcode> listCodes = new List<stdcode>();
     listCodes = (from row in dataTable.AsEnumerable() select row).ToList<stdcode>();


List<stdcode> ResultCodes = from codes in stdallCodes join dataCode in listCodes on codes.stdcode equals dataCode.stdcode select codes;

List listCodes=新列表（）；
listCodes=（从dataTable.AsEnumerable（）中的行选择行）；
List ResultCodes=from stdallCodes中的代码在codes上的listCodes中加入dataCode。stdcode等于dataCode。stdcode选择代码；

不转换时出现一些错误

我想要一个包含stdcode、code和value列的结果列表

请尝试以下操作：- 编辑

var query1 = listCodes.Join(query, x => x.STDCode, y => y.STDCode, (x, y) => new{
                y.Code,
                y.Value,
                y.STDCode,
                y.Description,
                x.MyField           
            } );

尝试更简单的方法：

 class Program
        {
            static void Main(string[] args)
            {
                DataTable dtName = new DataTable();
                dtName.Columns.Add("Code");
                dtName.Columns.Add("FirstName");
                dtName.Columns.Add("lastName");

                dtName.Rows.Add("1", "Abhishek", "Shukla");
                dtName.Rows.Add("2", "Deepak", "Singh");
                dtName.Rows.Add("3", "Vinay", "Negi");

                DataTable dtHomeTowns = new DataTable();
                dtHomeTowns.Columns.Add("Code");
                dtHomeTowns.Columns.Add("HomeTown");
                dtHomeTowns.Columns.Add("State");

                dtHomeTowns.Rows.Add("1", "Ajmer", "Rajasthan");
                dtHomeTowns.Rows.Add("2", "Bhiwadi", "Rajasthan");
                dtHomeTowns.Rows.Add("3", "Guwahati", "Orissa");

                var list = (from names in dtName.AsEnumerable()
                            join town in dtHomeTowns.AsEnumerable() on names["Code"] equals town["Code"]
                            select new
                            {
                                Code = names["Code"],
                                FirstName = names["FirstName"],
                                lastName = names["lastName"],
                                HomeTown = town["HomeTown"],
                                State = town["State"],
                            }).ToList();
                foreach (var item in list)
                {
                    Console.WriteLine(String.Format("Code:{0}, FirstName: {1},LastName :                 {2},HomeTown:{3},State:{4}", item.Code, item.FirstName, item.lastName, item.HomeTown, item.State));
                }

                Console.ReadKey();
            }
        }

---

希望这有帮助

stdcode

是您编写的某种类型吗？如何将数据表行转换为

stdcode

？您得到的确切错误是什么？当然可以..只想问..如果要在结果中包含此字段，我在listCodes中有另一个字段ID？？那么你将如何改变？@Shabz请参见编辑。例如，新字段是

MyField

。如何在linq中按计数对结果进行分组。我想按计数对结果进行分组。我想按stdcode的计数对结果进行分组。请参阅我在顶部的问题try this-var items=list.GroupBy（n=>n.code，（key，values）=>new{code=key，count values.count（），Val=values.ToList（）}）；

var query1 = listCodes.Join(query, x => x.STDCode, y => y.STDCode, (x, y) => new{
                y.Code,
                y.Value,
                y.STDCode,
                y.Description,
                x.MyField           
            } );

 class Program
        {
            static void Main(string[] args)
            {
                DataTable dtName = new DataTable();
                dtName.Columns.Add("Code");
                dtName.Columns.Add("FirstName");
                dtName.Columns.Add("lastName");

                dtName.Rows.Add("1", "Abhishek", "Shukla");
                dtName.Rows.Add("2", "Deepak", "Singh");
                dtName.Rows.Add("3", "Vinay", "Negi");

                DataTable dtHomeTowns = new DataTable();
                dtHomeTowns.Columns.Add("Code");
                dtHomeTowns.Columns.Add("HomeTown");
                dtHomeTowns.Columns.Add("State");

                dtHomeTowns.Rows.Add("1", "Ajmer", "Rajasthan");
                dtHomeTowns.Rows.Add("2", "Bhiwadi", "Rajasthan");
                dtHomeTowns.Rows.Add("3", "Guwahati", "Orissa");

                var list = (from names in dtName.AsEnumerable()
                            join town in dtHomeTowns.AsEnumerable() on names["Code"] equals town["Code"]
                            select new
                            {
                                Code = names["Code"],
                                FirstName = names["FirstName"],
                                lastName = names["lastName"],
                                HomeTown = town["HomeTown"],
                                State = town["State"],
                            }).ToList();
                foreach (var item in list)
                {
                    Console.WriteLine(String.Format("Code:{0}, FirstName: {1},LastName :                 {2},HomeTown:{3},State:{4}", item.Code, item.FirstName, item.lastName, item.HomeTown, item.State));
                }

                Console.ReadKey();
            }
        }