linq - 可以使用所谓的嵌入式查询而不是方法调用来表达 Distinct

Question

给出以下代码:

string[]  colors = {"red","green","blue","red","green","blue"};
var distinctColors = (from c in colors select c).Distinct();
distinctColors.Dump();

是否可以折叠电话 .Distinct()嵌入查询语法？

类似于 int T-SQL

select distinct color from TableofColors

Answer 1

C# 的查询表达式语法不包括“distinct”。然而，VB 确实如此——例如，来自 MSDN docs for VB's Distinct clause :

// VB
Dim customerOrders = From cust In customers, ord In orders _
                     Where cust.CustomerID = ord.CustomerID _
                     Select cust.CompanyName, ord.OrderDate _
                     Distinct

C# 等效项必须显式调用 Distinct()点符号。

但是，您的示例仍然可以简化:

string[]  colors = {"red","green","blue","red","green","blue"};
var distinctColors = colors.Distinct();
distinctColors.Dump();

不要认为您必须使用查询表达式才能使用 LINQ :)