C# - if condition in Linq select query with where clause

Question

How can I avoid If condition to this situation if userid is zero?

if (Userid == 0)
{
    var logList = service.GetLogDetails();
    var usernames = (from A in logList orderby A.FirstName select new { Name = A.FirstName + " " + A.SurName, ID = A.Id }).Distinct();
    var loginDate = (from A in logList select A.LogInTime.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)).Distinct();
    var logOutDate = (from A in logList select (A.LogOutTime ?? "Unknown").ToString().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)).Distinct();
}
else
{
    var logList = service.GetLogDetails();
    var usernames = (from A in logList where A.Id == Userid orderby A.FirstName select new { Name = A.FirstName + " " + A.SurName, ID = A.Id }).Distinct();
    var loginDate = (from A in logList where A.Id == Userid select A.LogInTime.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)).Distinct();
    var logOutDate = (from A in logList where A.Id == Userid select (A.LogOutTime ?? "Unknown").ToString().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)).Distinct();
}

where A.Id == Userid || Userid == 0

KMoussa
– KMoussa

2016-11-12 17:54:14 +00:00
Commented Nov 12, 2016 at 17:54 — KMoussa
– KMoussa, Commented Nov 12, 2016 at 17:54

Gilad Green · Accepted Answer · 2016-11-12 18:03:48Z

3

Use an || in you linq where clause. Also you can improve by querying the logList once and then applying the different projections on it:

var logList = service.GetLogDetails()
                     .Where(item => Userid == 0 || item.Id = Userid)
                     .ToList();

var usernames = (from A in logList 
                 orderby A.FirstName 
                 select new { Name = $"{A.FirstName} {A.SurName}", ID = A.Id }).Distinct();

var loginDate = (from A in logList 
                 select A.LogInTime.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)).Distinct();

var logOutDate = (from A in logList 
                  select (A.LogOutTime ?? "Unknown").ToString().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)).Distinct();

edited Nov 12, 2016 at 18:03

answered Nov 12, 2016 at 17:52

Gilad Green

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2 Comments

lashja Over a year ago

I have written like this as you say var logList = service.GetLogDetails().Where(item => item.Id == Userid || Userid == 0).ToList(); Now its working. Thanks

mybirthname Over a year ago

@AbhilashJA If his answer helped you, mark it as correct.

user1681317 · Accepted Answer · 2016-11-12 17:56:31Z

1

Modify your queries like this

var usernames = (from A in logList where A.Id = UserId || UserId == 0 ...

answered Nov 12, 2016 at 17:56

user1681317

1 Comment

Gilad Green Over a year ago

Though correct this is like an answer posted 4 minutes ago

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