How to C# Linq Order by using list of strings similar to MySql FIELD

Question

I have the following

List<WorkItemHeader>
WorkItemWorkItemHeader(string company, string division, string customerNumber, string imgCode, int sequence, string orderNumber, int lineNumber, DateTime importDate, int processType, int operatorID, int typeset, string product)

I would like to order my list by multiple properties (by Division, ImportDate, OrderNumber, LineNumber)

Division contains (ABC, XYZ, DEF, HIJ)

My requirement (and question) is, Division needs to be sorted by Division containing: (XYZ, ABC) first then by ImportDate, OrderNumber, LineNumber.

MySql has FIELD()

ORDER BY FIELD(position,'forward', 'midfielder', 'defender', 'goalkeeper')

T-SQL has CASE WHEN

ORDER BY CASE Position WHEN "forward" THEN 1
                   WHEN "defender" THEN 2
                   WHEN "midfielder" THEN 3
                   WHEN "goalkeeper" THEN 4 END

How can I simulate the sorting using Linq?

[See here](https://stackoverflow.com/questions/298725/multiple-order-by-in-linq) — kay, Apr 11 '18 at 15:50
That would work if I was simply ordering suchas: WorkItemHeaders = (List)WorkItemHeaders.OrderBy(x => x.Division).ThenBy(x => x.ImportDate).ThenBy(x => x.OrderNumber).ThenBy(x => x.LineNumber); I need Division ordered in a certain order using string values first. — Mike, Apr 11 '18 at 15:52

Justin Loveless · Accepted Answer · 2018-04-11T16:04:53.197

0

It sounds like you want to just get Division XYZ and ABC first, order those by the fields you specified, then order the rest, and then combine those results? You did not specify how you wanted to order the remaining divisions or the other fields, so I just did the default ascending order.

var firstOrder = header.Where(d => d.Division == "XYZ" || d.Division == "ABC").OrderByDescending(c => c.Division).ThenBy(d => d.ImportDate).ThenBy(d => d.OrderNumber).ThenBy(d => d.LineNumber).ToList();
var secondOrder = header.Where(d => d.Division != "XYZ" && d.Division != "ABC").OrderBy(c => c.Division).ThenBy(d => d.ImportDate).ThenBy(d => d.OrderNumber).ThenBy(d => d.LineNumber).ToList();
firstOrder.AddRange(secondOrder);

edited Apr 11 '18 at 16:04

answered Apr 11 '18 at 15:53

Justin Loveless

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Shouldn't the logical OR operator in the secondOrder line be a logical AND? – Philip Smith Apr 11 '18 at 16:04
If I have `string xxx = "XYZ,ABC";` could I do ... `.Where(d=>d.Division.Contains(xxx).OrderByDescending` ...? – Mike Apr 11 '18 at 16:19
`.Where(d=>d.Division.Contains(xxx)).OrderbyDescending`. You probably want to order the result of the where clause. – Justin Loveless Apr 11 '18 at 16:29
That's what I meant - forgot the paren. Let me try. – Mike Apr 11 '18 at 16:34
for the secondOrder, how would I do a NOT contains? – Mike Apr 11 '18 at 16:35
Would this work? `.Where(d => !d.Division.Contains(csvDivisions)).OrderBy` – Mike Apr 11 '18 at 16:43
Does the Contains("string1, string2") add an implicit AND or OR when using NOT? – Mike Apr 11 '18 at 16:47

How to C# Linq Order by using list of strings similar to MySql FIELD

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