C＃Linq查询以加入两个列表并将结果分配给组合框

Question

我有两个字符串列表

 Lista           Listb
 ------------------------
 apple           mango
 mango           grapes
 grapes          watermelon
 pineapple       orange
 banana

我想在组合框中显示lista的所有项目，还选择在这种情况下芒果和葡萄都通用的项目，并在组合框中进行预检查

combobox items
---------------------
 apple
 mango - checked
 grapes - checked
 pineapple
 banana 

Answer 1

以下应为您提供一个包含Lista值的列表以及有关是否应在IsChecked属性中检查列表中的项目的附加信息：

var result = Lista.Select(a => new 
                    {
                        Value = a,
                        IsChecked = Listb.Any(b => b == a)
                    }).ToList();

剩下的只是将结果绑定到组合框。 此步骤因您的平台（ASP.NET，WPF，Windows Form等，几乎都具有组合框）而异，并且，我相信每个元素在Internet上都有据可查，因此您应该首先阅读并尝试一个。

Answer 2

你可以做

var listA = new[] {"apple", "mango", "grapes", "pineapple", "banana"};
var listB = new[] {"mango", "grapes", "watermelon", "orange"};

var common = listA.Intersect(listB);

得到重叠

Answer 3

尝试在Linq中加入Left

var listA = new[] { "apple", "mango", "grapes", "pineapple", "banana" }.ToList();
var listB = new[] { "mango", "grapes", "watermelon", "orange" }.ToList();

var listCheckboxItem =
(
    from a in listA
    join b in listB on a equals b into lst
    from item in lst.DefaultIfEmpty()
    select new
    {
        Name = a,
        IsChecked = !(string.IsNullOrEmpty(item))
    }
).ToList();

Answer 4

Select可以获取一个布尔值列表，显示两个列表中都包含哪些元素。

List<string> Lista = new List<string>(new string[] { "apple", "mango", "grapes", "pineapple", "banana" });
List<string> Listb = new List<string>(new string[] {"mango","grapes","watermelon","orange"});

var inBoth = Lista.Select(x => Listb.Contains(x));
// False, True, True, False, False