C# 无法将类型“syste.collections.generics.list”隐式转换为“system.collections.generics.list”

我得到一个错误：

无法将类型System.Collections.Generics.List隐式转换为System.Collections.Generics.List

这是数据库连接问题吗？ 这是数据库连接错误吗？ MeritMAster_QuestionPeparsettings和MeritMAster.data.MeritMAster_QuestionPeparsettings是编译器的两种不同类型，这两种类型之间不存在转换

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您需要定义隐式或显式转换，或者手动转换它们。您可以使用各种技术，例如使用IQueryable.ForAll或IEnumerable。选择扩展方法。

sorry@Yuval。我找不到你。你能再多给我一点描述或代码来解决我的错误吗。请帮助我如何转换您能否显示MeritMAster_QuestionPaperSettings类和MeritMAster.data.MeritMAster_QuestionPeparSetting类或显示它们之间的关系。

public class DataManager
{
    public static void OnlineExamLists(
        out List<MeritMaste_QuestionPaperSettings> examQuestionSettings,
        out List<MeritMaster_QuestionBank> questionBanks, string examCode)
    {

        using (var dbcontext = new meritmasterEntities())
        {

            // var exam_code = dbcontext.MeritMaste_QuestionPaperSettings.Where(m => m.ID == examCode).FirstOrDefault().ex_code;
            //(from k in dbcontext.MeritMaste_QuestionPaperSettings where k.Status == true && k.ID == examCode select k.ex_code).ToList();

            examQuestionSettings = (from k in dbcontext.MeritMaste_QuestionPaperSettings 
                                    where k.Status == true && k.ex_code == examCode 
                                    select k).ToList();

            var examsettingslocal = examQuestionSettings.FirstOrDefault();

            var kabqu = new List<MeritMaster_QuestionBank>();
            var queBank = examsettingslocal == null
                ? kabqu
                : (from k in dbcontext.MeritMaster_QuestionBank
                    where k.Status == true && k.Course_ID == examsettingslocal.CourseId
                    select k).ToList();
            // questionBanks = queBank.ToList();

            var questionbanklocal = dbcontext.MeritMaste_QuestionPaperSettings.ToList();


            questionBanks = (from es in examQuestionSettings.ToList()
                                join qb in queBank.ToList() on new {p1 = (int) es.CourseId, p2 = (int) es.QuestionIds} equals
                                    new {p1 = (int) qb.Course_ID, p2 = (int) qb.ID}

                                where es.ex_code == examCode && es.Status == true && qb.Status == true
                                select qb).ToList();
            //join a in questionpaperlocal.ToList() on k.QuestionIds equals a.ID
            //where k.Status == true && a.Status == true
            ////orderby a.Id ascending
            //select k
        }
    }
}