CODEWITHSUNDEEP
c#linq
Elaine K
Elaine K

Reputation: 517

Where clause with if statement

Hi all and thanks in advance, I'm stumped on how to use a where clause with the conditional statement that I need to execute. I have two grids of information, one grid is dependent on the other for determining what shows. In the first grid the Date field can be a date or it can say Never.

The first grid's data is like so: 

ID       Date     Title
---      -----    ------
12       Never    Home
13       Never    School
14       Never    Work

The second grid will only show one row of the three depending on what the value of the Date field is, in this example it should be:

ID       Date     Title
---      -----    ------
12       Never    Home

This information is pulled into a List that I want to iterate through using LINQ. What I want to achieve is: 

If(All Date values == 'Never') 
    Then pull the first one (12)
else
    if(Date has value)
         then pull the first that has a date

myList.Where(??what goes here??).Select(t => t).FirstOrDefault();

Upvotes: 3

Views: 553

Answers (3)

Silas Reinagel
Silas Reinagel

Reputation: 4203

Since you have two rules, you will need an if condition somewhere.

The simplest form that I can think of is something like this:

return myList.All(x => x.Date == "Never") ? myList.FirstOrDefault() : myList.FirstOrDefault(x => x.Date != "Never");

Upvotes: -1

weston
weston

Reputation: 54781

var record = myList.FirstOrDefault(m => !m.Date.Equals("Never"))
               ?? myList.FirstOrDefault();

i.e. first one that doesn't equal never or null, and if null, just the first one (or null).

Upvotes: 8

Corey Adler
Corey Adler

Reputation: 16137

You're probably looking for something like this:

var record = myList.All(m => m.Date.Equals("Never")) 
               ? myList.FirstOrDefault() 
               : myList.FirstOrDefault(m => !m.Date.Equals("Never"));

For more on .All() just look at this MSDN post.

Upvotes: 7

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