Remove duplicates in the list using linq

Question

I have a class Items with properties (Id, Name, Code, Price).

The List of Items is populated with duplicated items.

For ex.:

1         Item1       IT00001        $100
2         Item2       IT00002        $200
3         Item3       IT00003        $150
1         Item1       IT00001        $100
3         Item3       IT00003        $150

How to remove the duplicates in the list using linq?

Answer 1

var distinctItems = items.Distinct();

To match on only some of the properties, create a custom equality comparer, e.g.:

class DistinctItemComparer : IEqualityComparer<Item> {

    public bool Equals(Item x, Item y) {
        return x.Id == y.Id &&
            x.Name == y.Name &&
            x.Code == y.Code &&
            x.Price == y.Price;
    }

    public int GetHashCode(Item obj) {
        return obj.Id.GetHashCode() ^
            obj.Name.GetHashCode() ^
            obj.Code.GetHashCode() ^
            obj.Price.GetHashCode();
    }
}

Then use it like this:

var distinctItems = items.Distinct(new DistinctItemComparer());