Linq获取指定的孩子和他们的父母

debugcn 发表于 Dev

学习者

我有两个班的父母和孩子。我想让所有满足其子女条件的父母，例如所有父母及其子女。我想使用Linq。我使用了以下Linq查询，它返回了所有带女童的父母，但是，儿童名单也包含了男童。我只想让父母和他们的小孩来List<Parent> parentsAndFemaleChildren。请参阅以下Linq查询：

List<Parent> parentsAndFemaleChildren = Parents
    .Where(p => p.Children.Any((c => c.Gender == "Female")))
    .ToList();

填充数据的代码如下所示。

public class Parent
{
    public int ParentId {get;set;}
    public string ParentName {get;set;}
    public List<Child> Children {get;set;}
}
public class Child
{
    public int ChildId {get;set;}
    public string ChildName {get;set;}
    public string Gender {get;set;}
    public int ParentId {get;set;}
}

我已经按照以下方式填充了数据。

public static void Main()
    {
        List<Parent> Parents = new List<Parent>();

        Parent p1 = new Parent();
        p1.ParentId = 1;
        p1.ParentName = "Parent 1";
        Parents.Add(p1);    


        Child p1C1 = new Child();
        p1C1.ChildId = 1;
        p1C1.ChildName = "Parent 1 Child 1";
        p1C1.Gender = "Male";
        p1C1.ParentId = 1;

        p1.Children = new List<Child>();

        p1.Children.Add(p1C1);

        Child p1C2 = new Child();
        p1C2.ChildId = 2;
        p1C2.ChildName = "Parent 1 Child 2";
        p1C2.Gender = "Female";
        p1C2.ParentId = 1;

        p1.Children.Add(p1C2);

        Parent p2 = new Parent();
        p2.ParentId = 2;
        p2.ParentName = "Parent 2";
        Parents.Add(p2);

        Child p2C1 = new Child();
        p2C1.ChildId = 3;
        p2C1.ChildName = "Parent 2 Child 1";
        p2C1.Gender = "Female";
        p2C1.ParentId = 2;

        p2.Children = new List<Child>();

        p2.Children.Add(p2C1);

        Child p2C2 = new Child();
        p2C2.ChildId = 4;
        p2C2.ChildName = "Parent 2 Child 2";
        p2C2.Gender = "Male";
        p2C2.ParentId = 2;

        p2.Children.Add(p2C2);

        Parent p3 = new Parent();
        p3.ParentId = 3;
        p3.ParentName = "Parent 3";
        Parents.Add(p3);

        Child p3C1 = new Child();
        p3C1.ChildId = 5;
        p3C1.ChildName = "Parent 3 Child 1";
        p3C1.Gender = "Male";
        p3C1.ParentId = 3;

        p3.Children = new List<Child>();

        p3.Children.Add(p3C1);


        DisplayFemaleChildrenAndParents(Parents);
    }

    public static void DisplayFemaleChildrenAndParents(List<Parent> Parents)
    {
        List<Parent> parentsAndFemaleChildren = Parents.Where(p => p.Children.Any((c => c.Gender == "Female"))).ToList();
        Console.WriteLine("\nShould Display Parents and their Female children details ONLY\n");
        foreach(Parent p in parentsAndFemaleChildren)
        {       
            Console.WriteLine("***********");           
            foreach(Child c in p.Children)
            {               
                Console.WriteLine(p.ParentName + " - " + c.ChildName + " - " + c.Gender);
            }
            Console.WriteLine("***********");
        }
    }

完整的代码可以看出，并通过运行拨弄DOTNET点击此处。

升压

如果您需要过滤仅有女童的父母，则应使用ALLlinq方法。

MSDN关于.All方法说：

确定序列中的所有元素是否都满足条件。

List<Parent> parentsAndFemaleChildren = Parents
    .Where(p => p.Children.All((c => c.Gender == "Female"))).ToList();

如果您想让父母育有至少一个女童，并且只选择女童，则可以使用以下select方法Where：

List<Parent> parentsAndFemaleChildren = Parents
    .Where(p => p.Children.Any((c => c.Gender == "Female")))
    .Select(s => new Parent { ParentId = s.ParentId, ParentName = s.ParentName, 
        Children = s.Children.Where(ch => ch.Gender == "Female").ToList()}).ToList();

本文收集自互联网，转载请注明来源。

如有侵权，请联系[email protected] 删除。