asp.net core razor how to select a specific date in a sequence

Marius Vasile

I have a sequence of dates. I can select the lowest with

SEDateLow = await _context.IncidentSeqEvents.Include(s => s.IncidentSeqEventMain)
                                                                    .ThenInclude(s => s.InvestigationRCA)
                                                                    .Where(s => s.IncidentSeqEventMain.InvestigationRCA.OrgID == orgid && s.IncidentSeqEventMain.InvestigationRCA.IdINV == idinv)
                                                                    .Select(s => s.EventTime)
                                                                    .MinAsync();

How do I select the second date value in the row and then third and so on?

5 Replies

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Sachin Singh5y ago
Accepted answer
Always use OrderBy with Take() and Skip() to solve such problems.
var All= await _context.IncidentSeqEvents.Include(s => s.IncidentSeqEventMain)
.ThenInclude(s => s.InvestigationRCA)
.Where(s => s.IncidentSeqEventMain.InvestigationRCA.OrgID == orgid && s.IncidentSeqEventMain.InvestigationRCA.IdINV == idinv)
.Select(s => s.EventTime);

var second= All.OrderByDescending(x=>x.EventTime).Skip(1).Take(1);

var third=All.OrderByDescending(x=>x.EventTime).Skip(2).Take(1);

var Nth=All.OrderByDescending(x=>x.EventTime).Skip(n).Take(1);
Marius Vasile5y ago
I am going to have a simpler approach, I think will be easier to implement and simple to maintain, by giving the user the oportunity to edit the OrderNo and change whenever is required
Marius Vasile5y ago
Let me try to explain better what I want to achieve. I have a sequents of events, each with OrderNo and DateTime. in the sequence, it may be required to add another event, with a DateTime not in the sequence, not higher that the last entered. I want that event to be assigned an OrderNo in sequence based on the datetime. right now the sequence looks like below

I want the numbering to automatically adjust based on the DateTime. Am I asking too much? Is it difficult to achieve?
Sachin Singh5y ago
Then OrderByDescending() will give you all Dates from min to max, in a sequence.
For assigning autoincrement better is to add the OrderNo column in the database as identity.
Marius Vasile5y ago
That makes sense but I don't know how many dates are in the sequence. And what I want is to assign an auto incremental OrderNo for each date, starting from lowest to highest no matter if I insert a date in the middle of the sequence at any time