如何使用LINQ to SQL执行CROSS JOIN？

如何使用LINQ to SQL执行CROSS JOIN？

1> Steve Morgan..：

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交叉连接只是两组笛卡尔积.它没有明确的连接运算符.

var combo = from p in people
            from c in cars
            select new
            {
                p.Name,
                c.Make,
                c.Model,
                c.Colour
            };

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`people.SelectMany(p => cars,(p,c)=> new {...})`

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您如何用lambda表示法写出`p来自汽车中c来自人中c来自汽车中c'中？

2> Rzv.im..：

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用同样的事情linq扩展方法:

var names = new string[] { "Ana", "Raz", "John" };
var numbers = new int[] { 1, 2, 3 };
var newList=names.SelectMany(
    x => numbers,
    (y, z) => { return y + z + " test "; });
foreach (var item in newList)
{
    Console.WriteLine(item);
}

3> Mark Cidade..：

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根据史蒂夫的回答,最简单的表达方式是:

var combo = from Person in people
            from Car    in cars
            select new {Person, Car};

4> amoss..：

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A Tuple是笛卡尔积的良好类型:

public static IEnumerable> CrossJoin(IEnumerable sequence1, IEnumerable sequence2)
{
    return sequence1.SelectMany(t1 => sequence2.Select(t2 => Tuple.Create(t1, t2)));
}