将列表转换为字符串列表

Question

请看代码:

// get column list from entity framework
var listID = from Ines in ineContext.IneDetailRecords
             select Ines.InePIN.ToString().ToList();
string PIN = something;
if(!listID.Contains(PIN))
    // save it to DB

InePIN是SQL Server DB中的一个cloumn,类型是varchar(20).

例外是:

Instance argument: cannot convert from 'System.Linq.IQueryable<System.Collections.Generic.List<char>>' to 'System.Linq.ParallelQuery<string>'

Answer 1

您需要在查询结果上应用ToList方法,而不是在所选列上应用ToList方法 Ines.InePIN.ToString().ToList()

更改

var listID = from Ines in ineContext.IneDetailRecords
                                       select Ines.InePIN.ToString().ToList();

至

var listID = (from Ines in ineContext.IneDetailRecords
                                       select Ines.InePIN.ToString()).ToList();