add object to list with properties at same time

I have,

List<Items> itemDetails = new List<Item>();
itemDetails.Add(new Item { isNew = true, Description = "test description" });

Why i can't write above code like 

List<Items> itemDetails = new List<Item>().Add(new Item { isNew = true, Description = "test description" });

It gives error

Cannot implicitly convert type 'void' to 'System.Collections.Generic.List<>
Jon Skeet
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quotationmark

When you call Add, that has a void return type... which is why you're getting the error. The overall result of the expression new List<Item>().Add(...) is void.

However, you can use a collection initializer:

List<Item> itemDetails = new List<Item>
{
    new Item { isNew = true, Description = "test description" },
    new Item { isNew = false, Description = "other description" }
};

That's basically telling the compiler to convert each element within the collection initializer into an Add call for you.

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