相关疑难解决方法(0)

从性能的角度来看,你应该使用"嵌套的foreach"或"lambda/linq查询"？

我试图基于多个列(attribute1_name,attribute2_name)获取不同的行,并使用Linq-to-Dataset从datatable获取数据行.

我想要这样的结果

attribute1_name    attribute2_name
--------------     ---------------

Age                State
Age                weekend_percent
Age                statebreaklaw
Age                Annual Sales
Age                Assortment

如何做薄Linq到数据集？

这段代码:

var customers = from cust in Customers
    group cust by new {cust.Country} into grouping
    select new
    {
        Country = grouping.Key.Country,
        Customers = grouping
    };

customers.ToList().ForEach(g => 
    Console.WriteLine("{0} has {1} customers: {2}", 
        g.Country, 
        g.Customers.Count(), 
        String.Join(", ",g.Customers.Select(x => "#. " + x.CompanyName).ToArray())
    ));

customers.Dump();

产生这些结果:

Argentina has 3 customers: #. Cactus Comidas para llevar, #. Océano Atlántico Ltda., #. Rancho grande
Austria has 2 customers: #. Ernst Handel, #. Piccolo und mehr
Belgium has 2 customers: #. Maison Dewey, #. Suprêmes …