Question

我试图在获取记录时比较存储在sql中的一个月的日期，但它会抛出异常。

public partial class LateRequest
{
    public int LateRequestID { get; set; }
    public Nullable<int> EmpID { get; set; }
    public Nullable<int> TeamLeadAppr { get; set; }
    public Nullable<int> DeptLeadAppr { get; set; }
    public Nullable<System.DateTime> lateDate { get; set; }
}

在我的计算课上我有;

public int getMonthlyLatesApproved(int empId)
{
    DateTime today = DateTime.Now;
    var getMonth = today.Month
    var lateApproved = (from obj in db.LateRequests
                        where obj.EmpID == empId
                        && obj.TeamLeadAppr == 1 && obj.DeptLeadAppr == 1
                        && obj.lateDate.Value.ToString("mm") == getMonth.ToString()
                        select obj).Count();
    return lateApproved;
}

这不起作用所以我尝试使用LINQ，如：

return db.LateRequests.Where(x => x.EmpID == empId && x.TeamLeadAppr == 1 && x.DeptLeadAppr == 1 &&
                                  x.lateDate.Value.ToString("mm") == getMonth.ToString()).Count();

此操作失败，我将其读为here并尝试使用AsEnumerable()

如下;

 return db.LateRequests.Where(x => x.EmpID == empId && x.TeamLeadAppr == 1 && x.DeptLeadAppr == 1 &&
                                  x.lateDate.Value.ToString("mm") == getMonth.ToString()).AsEnumerable().Count();

`LINQ to Entities does not recognize the method 'System.String ToString(System.String)' method.when i try to format my date

我需要了解在检索记录时如何将c-sharp与sql命令混合使用？

Answer 1

您需要的是SqlFunctions.DatePart方法。

&& SqlFunctions.DatePart("month", obj.lateDate) == getMonth

LINQ to Entities无法识别方法'System.String ToString（System.String）'

1 个答案: