/// <summary>

/// 自定义去重复

/// </summary>

public static IEnumerable<TSource> IDistinctBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)

{

var seenKeys = new HashSet<TKey>();

return source.Where(element => seenKeys.Add(keySelector(element)));

}