定义的λ外子查询迭代变量评价

Question

从LINQ Quiz问题和答案，Q4和Q5

随着colors阵列的数量为：

string[] colors = { "green", "brown", "blue", "red" }; 

和查询从回答到Q4：

var query = 
    from c in colors 
    where c.Length == colors.Max (c2 => c2.Length) 
    select c; 

我是否正确理解外部查询迭代表达式c2.Length将被评估16次？

即，用于在colors阵列的每个项目с，所述colors.Max (c2 => c2.Length)将被计算一次，即Max()计算将进行4次共i。并且对于每个Max()评估，c2.Length将被发现4次？

Answer 1

是的，这是正确的。易于检查，以及如果你有LINQPad尝试：

string[] colors = { "green", "brown", "blue", "red" }; 

int count = 0; 

var query = 
    from c in colors 
    where c.Length == colors.Max (c2 => 
     { 
      count.Dump(); 
      count++; 
      return c2.Length; 
     } 
    ) 
    select c; 

query.Dump();