WHERE clause in LINQ statement that pulls specific match or everything if no match found

Question

I am trying to write a LINQ statement that will pull all the items from a table where the column Type matches what the user selects in a dropdown menu but if no matches are found then it returns ALL the items from the table regardless of the Type. I have gotten it to return all the items that match the user’s selection but I cannot figure out what code needs to be added so that if no matches are found it defaults to pulling all the items in the table.

Current Code:

(from i in db.ItemTypeTranslations
    join st in db.SectionTranslations
    on i.ItemType.SectionID equals st.SectionID
    where i.CultureID == 1 && i.ItemType.SectionID == SelectedSection
    select new
    {
       st.SectionID,
       st.Title,
       i.ItemTypeName
    }).ToList();

Alan Gilbert · Answer 1 · 2013-04-30T00:13:00.430

1

How about

where i.CultureID == 1 && (i.ItemType.SectionID == SelectedSection || String.IsNullOrEmpty(SelectedSection))

I am assuming that SelectedSection is a string. If not, the principle will be the same: Where (SectionID == SelectedSection OR SelectedSection == some-default-value)

Edit: I just re-read your question, and realized that I'm answering the wrong question.

edited Apr 30 '13 at 00:13

answered Apr 29 '13 at 23:42

Alan Gilbert

365
2
9

score 1 · Accepted Answer · answered Apr 29 '13 at 23:42

1

You can use the ? operator to turn your where clause into a conditional and have your current select as the successful branch and the select that returns everything as the unsuccessful branch.

Similar question asked on MSDN

answered Apr 29 '13 at 23:42

Maggy May

233
1
7

score 1 · Answer 3 · 2013-05-01T00:55:15.980

Thanks Maggy May. That helped me a lot I ended up with this code that looks to be working:

(from i in db.ItemTypeTranslations
                                          join st in db.SectionTranslations
                                          on i.ItemType.SectionID equals st.SectionID
                                          where (SelectedSection == 0 ? true : i.ItemType.SectionID == SelectedSection) && i.CultureID == 1
                                          select new
                                          {
                                              i.ItemTypeID,
                                              st.Title,
                                              i.ItemTypeName
                                          }).ToList();

The orginal code I posted here was not working but with a slight tweek it is working now. I updated the code block with the confirmed working code. — , May 01 '13 at 00:55

WHERE clause in LINQ statement that pulls specific match or everything if no match found

3 Answers3