public static IEnumerable<TSource> Distinct<TSource>(this IEnumerable<TSource> source,IEqualityComparer<TSource> comparer
)

类型：System.Collections.Generic.IEnumerable<TSource>
指的是从中删除重复元素的序列

类型 : System.Collections.Generic.IEqualityComparer<TSource>
这个是与原数据的比较值

类型: System.Collections.Generic.IEnumerable<TSource>
返回原数据中不重复的序列

public class Product
{public string Name { get; set; }public int Code { get; set; }
}// 产品类的自定义比较器
class ProductComparer : IEqualityComparer<Product>
{// 如果产品的名称和产品编号相同，则产品相同public bool Equals(Product x, Product y){//检查比较对象是否引用相同的数据if (Object.ReferenceEquals(x, y)) return true;//检查所比较的对象是否为空if (Object.ReferenceEquals(x, null) || Object.ReferenceEquals(y, null))return false;//检查产品的属性是否相等return x.Code == y.Code && x.Name == y.Name;}// 如果Equals（）对一对对象返回true// 那么GetHashCode（）必须为这些对象返回相同的值。那么GetHashCode（）必须为这些对象返回相同的值。public int GetHashCode(Product product){//检查该对象是否为空if (Object.ReferenceEquals(product, null)) return 0;//如果它不为空，获取名称字段的

hashCode

 int hashProductName = product.Name == null ? 0 : product.Name.GetHashCode(); //获取代码字段的hashCode int hashProductCode = product.Code.GetHashCode(); //计算产品的hashCode return hashProductName ^ hashProductCode; } }

Product[] products = { new Product { Name = "apple", Code = 9 }, new Product { Name = "orange", Code = 4 }, new Product { Name = "apple", Code = 9 }, new Product { Name = "lemon", Code = 12 } };//排除重复

IEnumerable<Product> noduplicates =products.Distinct(new ProductComparer());foreach (var product in noduplicates)Console.WriteLine(product.Name + " " + product.Code);/*返回的值如下:apple 9 orange 4lemon 12
*/