[英]How to do LINQ Cross Join With Dot Notation
我知道如何以點表示法編寫查詢表示聯接,但是如何編寫以點表示法編寫的交叉聯接?
List<Alpha> als = new List<Alpha>{new Alpha(), new Alpha()};
List<Bravo> bros = new List<Bravo>{new Bravo(), new Bravo()};
//so far so good.
var res = from a in als
from b in bros
select new { A = a, B = b };
var what = res.ToArray();
//hmmmm. Not so sure.
var result = als.Join(bros, null, null, (x, y) => new { X = x, Y = y });
提出此問題的另一種方式:當C#編譯器將交叉聯接查詢表示形式無形地轉換為點表示法時,該點表示法是什么樣的?
我想這是
als.SelectMany(x => bros, (a, b) => new {A = a, B = b});
als.SelectMany(a => bros.Select(b => new {A = a, B = b}));
它看起來應該像這樣:
var res = als.Join(bros,
alsItem => alsItem.IdToJoin,
brosItem => brosItem.OtherId,
(alsItem, brosItem) => {X = alsItem, Y = brosItem});
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