C# 无法将类型“System.Collections.Generic.List”隐式转换为“System.Collections.Generic.List”

我已经看过stackoverflow中提供的所有解决方案，但没有得到解决方案。下面是我的代码

private static List<CombinedData> CombineReport(List<TimesheetUserPaycodeReport> timesheetUserPayCodeData, List<TimesheetReportData> reportData)
        {
            List<CombinedData> combinedReportData = new List<CombinedData>();
            return combinedReportData = (from ts in timesheetUserPayCodeData
            join rd in  reportData on new {ts.LoginName,ts.EntryDateString } equals new {rd.LoginName,rd.EntryDateString }
            select new { rd.EmployeeId,rd.LoginName, rd.LastName, rd.FirstName,rd.StartDateString,
                rd.EndDateString,rd.UserId,rd.EntryDateString,rd.ApprovalStatus,ts.PayCodeHours,
                ts.PayCodeCode,rd.ProjectCode,rd.OTRTicket,rd.ActivityCode,rd.ExportOn,rd.ApprovedOnString,rd.SubmittedOnString,rd.TimesheetId}).ToList();   

我得到以下错误：

Cannot implicitly convert type 'System.Collections.Generic.List<AnonymousType#1>' to 'System.Collections.Generic.List<TimeSheetExport.CombinedData>

---

您正在尝试创建一个异常类型的列表，而不是列表。 试一试

您试图从一个方法返回匿名类型的列表，该方法 需要返回列表。新的{}将创建 匿名类型列表，因此您需要将列表创建为 方法的返回类型

我猜，您的CombinedData类包含您要返回的所有字段，然后只需按以下方式更改查询：

private static List<CombinedData> CombineReport(List<TimesheetUserPaycodeReport> timesheetUserPayCodeData, List<TimesheetReportData> reportData)
        {
            List<CombinedData> combinedReportData = new List<CombinedData>();
            return combinedReportData = (from ts in timesheetUserPayCodeData
            join rd in  reportData on new {ts.LoginName,ts.EntryDateString } equals new {rd.LoginName,rd.EntryDateString }
            select new CombinedData   /// Create CombinedData object here, not anonymous type
            {  
              EmployeeId = rd.EmployeeId,
              LoginName = rd.LoginName, 
              LastName = rd.LastName, 
             ------ so on for remaining fields
             }).ToList();

---

错误很明显。您试图从需要返回Listnamespace TimeSheetExport{[DelimitedRecord，]class CombinedData{[FieldQuoted]公共字符串EmployeeId；[FieldQuoted]的方法返回匿名类型的列表public string LoginName；请不要尝试在注释中添加代码-如果要显示更多代码，请编辑问题并添加它。如果突出显示代码块并点击{}ToListSide注意：您应该提供指向您尝试过的方法的链接，并简要说明为什么它在您的案例中不起作用，而不是搜索大量文本。

private static List<CombinedData> CombineReport(List<TimesheetUserPaycodeReport> timesheetUserPayCodeData, List<TimesheetReportData> reportData)
        {
            List<CombinedData> combinedReportData = new List<CombinedData>();
            return combinedReportData = (from ts in timesheetUserPayCodeData
            join rd in  reportData on new {ts.LoginName,ts.EntryDateString } equals new {rd.LoginName,rd.EntryDateString }
            select new CombinedData   /// Create CombinedData object here, not anonymous type
            {  
              EmployeeId = rd.EmployeeId,
              LoginName = rd.LoginName, 
              LastName = rd.LastName, 
             ------ so on for remaining fields
             }).ToList();