c# - LINQ to Entities 无法识别该方法并且无法将此方法转换为存储表达式

Question

我使用 Entity Framework 在我的数据库中调用某个日期。但是我下面的代码给出了这个错误

LINQ to Entities 无法识别“SchoolBreifcase.Compliance get_Item(Int32)”方法，并且无法将此方法转换为存储表达式。

这是我的完整代码

FinancialCompliance financialCompliance = new FinancialCompliance();
            List<Compliance> compliance = null;
            if (HttpContext.Current.User.IsInRole("SchoolAdmin"))
            {

                compliance = datamodel.Compliances.Where(u => u.UserId == userId).OrderBy(c => c.AddedDate).ToList();

            }
            if (HttpContext.Current.User.IsInRole("User"))
            {
                compliance = datamodel.Compliances.Where(u => u.VerifierId == userId || u.OwnerId == userId).OrderBy(c => c.AddedDate).ToList();
            }
            if (compliance != null)
            {
                for (int i = 1; i < compliance.Count; i++)
                {
                    financialCompliance = datamodel.FinancialCompliances.Where(f => f.ComplianceId == compliance[i].ComplianceId).SingleOrDefault();
                    if (compliance.Count == i)
                    {
                        return financialCompliance;
                    }
                }
            }
            return financialCompliance;
        }

这一行给出了错误:

financialCompliance = datamodel.FinancialCompliances.Where(f => f.ComplianceId == compliance[i].ComplianceId).SingleOrDefault();

无助于堆栈溢出答案我在这个堆栈溢出站点中找到了一些答案

LINQ to Entities does not recognize the method

等..但对我没有帮助。所以我问了这个问题。请不要有人因为已经问过而关闭这个问题

Answer 1

您需要创建一个变量来引用 compliance[i].ComplianceId 然后稍后使用它。

for (int i = 1; i < compliance.Count; i++)
{
    var complianceId = compliance[i].ComplianceId;
    financialCompliance = datamodel.FinancialCompliances.Where(f => f.ComplianceId == complianceId ).SingleOrDefault();
    if (compliance.Count == i)
    {
        return financialCompliance;
    }
}