將C＃組數據庫查詢結果嵌入到嵌套的泛型列表中

Question

我從存儲過程中獲取查詢數據，並且需要將其分組爲3個通用列表。我不知道如何解決這個問題。

以下是從數據的查詢結果如下總結：

Child | Parent | GrandChildren 
a2  | a1  | a30 
a2  | a1  | a31 
a2  | a1  | a32 

b2  | b1  | b30 
b2  | b1  | b31 

c2  | c1  | c30 

d2  | d1  | d30 
d2  | d1  | d31 
d3  | d1  | d32 
d3  | d1  | d33 

這裏是我想對數據進行分組。

public class Parent 
{ 
    public int ID { get; set; } 
    public string Name { get; set; } 
    public List<Child> Children { get; set; } 
} 

public class Child 
{ 
    public int ID { get; set; } 
    public string Name { get; set; } 
    public List<GrandChild> GrandChildren { get; set; } 
} 

public class GrandChild 
{ 
    // numerous properties. 
} 

這是我試過的，但沒有運氣。

var data = Repository.GetData(); 
var groupedData = from d in data 
        where d.Parent > 0 
        group d by d.Parent into ParentGroup 
        select parentGroup.ToList(); 

// Result: Grouped list of "Parent", not with grouped "Child" and grouped "GrandChildren" as per desired structure above. 

Answer 1

您將不得不將子孫也分組。像這樣的事情：

var data = Repository.GetData(); 

// Group the Grandchildren first 
var grandkids = from d in data 
       where d.Child > 0 
       group d by d.Child into GrandChildGroup 
       select new Grandchild { 
        // Assign grand child properties here 
       }; 

// Group the Children 
var children = from d in data 
       where d.Parent > 0 
       group d by d.Parent into ChildGroup 
       select new Child { 
        // Assign child properties here 
        Grandchildren = (from gc in grandkids 
            where gc.Parent = d.Child 
            select gc).ToList() 
       }; 

// Now group the parents 
var groupedData = from p in data 
        select new Parent { 
         // Assign parent properties here 
         Children = (from kid in children 
            where kid.Parent = p.Parent 
            select kid).ToList() 
        }.ToList();