how to pass optional parameter in linq where condition

Question

I have a action in MVC controller

public ActionResult ExportExcel(string ReportType,DateTime? FromDate,DateTime? ToDate)
{
     var query = UnitOfWork.RepoTestResAnalysis.GetAll();
     var QueryData = query.Where(s => s.MSO == ms && (FromDate != null && (s.TEST_DATE.Value >= FromDate)) && (ToDate!=null && (s.TEST_DATE.Value<=ToDate))).ToList();
}

Now If FromDate and ToDate are null then I am getting QueryData Count is Zero. But I need all records. So Can anyone tell me how can I get expected result. While FromDate & ToDate has value then I am getting expected result.

Answer 1

According to the information you have provided

Change you below statement:

var QueryData = query.Where(s => s.MSO == ms && (FromDate != null && (s.TEST_DATE.Value >= FromDate)) && (ToDate!=null && (s.TEST_DATE.Value<=ToDate))).ToList();

To

var QueryData = query.Where(s => s.MSO == ms && (FromDate == null || (s.TEST_DATE.Value >= FromDate)) && (ToDate == null || (s.TEST_DATE.Value<=ToDate))).ToList();

If the FromDate Or ToDate will be equal to NULL , it won't check them against s.TEST_DATE.Value .

Answer 2

You can do it like below also: Change QueryData assignment to:

var QueryData = query.Where(s => s.MSO == ms && 
(s.TEST_DATE.Value >= (FromDate ?? DateTime.MinValue)) && 
(s.TEST_DATE.Value <= (ToDate ?? DateTime.MaxValue))).ToList();

Answer 3

I know it's an old question, but I will be glad if my code can help anybody. I think following implementation will be the short and easy to read:

public ActionResult SomeMethod(string ReportType, DateTime? FromDate, DateTime? ToDate)
{
    var query = UnitOfWork.RepoTestResAnalysis.GetAll();
    var QueryData = query.Where(x => x.DateField >= (FromDate ?? x.DateField) && x.DateField <= (ToDate ?? x.DateField).ToList();                 
}