如何使用 LINQ 执行 SELECT UNIQUE？

我有一个这样的清单:

Red
Red
Brown
Yellow
Green
Green
Brown
Red
Orange

我正在尝试用 LINQ 做一个 SELECT UNIQUE，也就是说，我想

Red
Brown
Yellow
Green
Orange


var uniqueColors = from dbo in database.MainTable
where dbo.Property == true
select dbo.Color.Name;

然后我把它改成

var uniqueColors = from dbo in database.MainTable
where dbo.Property == true
select dbo.Color.Name.Distinct();

没有成功。第一个 select得到所有的颜色，那么我如何修改它只得到唯一的值？

如果有一个更好的方法来构造这个查询，我会非常乐意走这条路。

我如何去编辑它，以便我可以有 .OrderBy( "column name" )即字母顺序的颜色名称，所以名称属性？

我一直收到一条信息:

无法从用法推断类型参数。请尝试显式指定类型参数。

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小开

var uniqueColors = (from dbo in database.MainTable
where dbo.Property == true
select dbo.Color.Name).Distinct();

小开

Using query comprehension syntax you could achieve the orderby as follows:

var uniqueColors = (from dbo in database.MainTable
where dbo.Property
orderby dbo.Color.Name ascending
select dbo.Color.Name).Distinct();

小开

最佳答案

The Distinct() is going to mess up the ordering, so you'll have to the sorting after that.

var uniqueColors =
(from dbo in database.MainTable
where dbo.Property == true
select dbo.Color.Name).Distinct().OrderBy(name=>name);

小开

var unique = (from n in test group n by n into g where g.Count()==1 select g.Key.ToString());