Most often, we do with List and find one or more items in list. Imagine that we want to look for a product in List using PrimaryKey. The code is: foreach (Product p in this.Products) { if (p.PrimaryKey == primaryKey) return p; } We also have another way that makes it better in performance as well as readability. Predicate condition = delegate(Product p) { return p.PrimaryKey.Equals(primaryKey); }; return this.Products.Find(condition); To find all items: this.Products.FindAll(condition); Both of them return NULL if not found.