You can use the LINQ Concat
and ToList
methods:
var allProducts = productCollection1.Concat(productCollection2)
.Concat(productCollection3)
.ToList();
Note that there are more efficient ways to do this – the above will basically loop through all the entries, creating a dynamically sized buffer. As you can predict the size to start with, you don’t need this dynamic sizing… so you could use:
var allProducts = new List<Product>(productCollection1.Count +
productCollection2.Count +
productCollection3.Count);
allProducts.AddRange(productCollection1);
allProducts.AddRange(productCollection2);
allProducts.AddRange(productCollection3);
(AddRange
is special-cased for ICollection<T>
for efficiency.)
I wouldn’t take this approach unless you really have to though.