CODEWITHSUNDEEP
c#asp.netlinq
Bex
Bex

Reputation: 4918

list contains an ID in linq

I am trying to find a linq query so I can write it in an if statement.

Pseudo code:

IDList is a list of ints List< int >

if (IDList.Contains (Object.Id)) Do something

but I can't seem to work out what need.

In none-linq this works:

  foreach(int id in IDList )
     {
        if (id == Object.Id)
            break;
     }

but I want it as one line if possible.

I first tried this:

IDList.Contains(Object.Id);

but this throws a compile error

I'm wondering should it be one of these two?

  IDList.Any(id => id == Object.Id)

or 

IDList.Exists(id => id == Object.Id);

I don't completely understand how the lambdas and things work or the difference between andy and exists so I'm not sure if I'm along the wrong line?

Upvotes: 12

Views: 35351

Answers (2)

Dmitriy
Dmitriy

Reputation: 1972

 IDList.Any(id => id == Object.Id)

Is ok, it will return you true if at least one element, that satisfies your predicate, exists.

Upvotes: 8

Matteo Mosca
Matteo Mosca

Reputation: 7448

You can simply do this:

if (MyList.Any(c => c.Id == MyObject.Id)) { }

Assuming that MyList is an IEnumerable<T> (or anything that derives from IEnumerable<T>) where T is an object that has a property named Id of the same type of the property Id on the MyObject instance.

Upvotes: 27

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