我个人会更改Web服务要做到这一点的过滤，并在服务器排序以降低带宽需求，很可能返回简单的数据类型或自定义类（未数据表或类似的话）。但LINQ会做的工作......（更新在重新阅读的问题）

Personally I'd change the web-service to do this filtering and sorting at the server to reduce bandwidth needs, probably returning a simple data-type or custom class (not DataTable or anything similar). But LINQ would do the job... (updated after re-reading the question)

var rows = dataset.Tables[0].AsEnumerable()
    .DistinctBy(row => row.Field<string>("account number"))
    .OrderBy(row => row.Field<string>("account name"))
    .ToArray();

使用自定义的 DistinctBy 方法：

    static IEnumerable<TSource> DistinctBy<TSource, TValue>(
        this IEnumerable<TSource> source,
        Func<TSource, TValue> selector)
    {
        HashSet<TValue> unique = new HashSet<TValue>();
        foreach (var item in source)
        {
            if (unique.Add(selector(item))) yield return item;
        }
    }