如何将分层列表转换为平面列表

Question

通常我们将平面列表转换为分层列表，但就我而言，我想将分层列表转换为平面列表。

我有一个分层list<T>，我想将此分层列表转换为平面list<T>类。

假设我有一个下面的分层列表

 Parent1
  --- Child1 ,F1
  ----Child2, F2
  ----Child2, F3
 Parent2
  ----Child2,F2
  ----Child4,F6
  Parent3
  --- Child1 ,F1

我需要如下输出：

 Parent1, Child1,F1
 Parent1, Child2,F2
 Parent1, Child2,F3
 Parent2,Child2,F2
 Parent2,Child4, F6
 Parent3, Child1,F1

Answer 1

它可能

不是最优化的解决方案（我认为它可以进一步最小化，我有一个更简洁的版本 - 但这种形式是我使用最多的）

这就是我一直在使用的东西

public static IEnumerable<T> FlattenHierarchy<T>(this T node,
                                Func<T, IEnumerable<T>> getChildEnumerator)
{
    yield return node;
    if (getChildEnumerator(node) != null)
    {
        foreach (var child in getChildEnumerator(node))
        {
            foreach (var childOrDescendant
                        in child.FlattenHierarchy(getChildEnumerator))
            {
                yield return childOrDescendant;
            }
        }
    }
}

你可以像这样使用它

folder.FlattenHierarchy(x => x.SubFolders)

Answer 2

最后我得到了解决方案：

public class RNode 
        {
            public string Id;
            public long ID;
            public string name;
            public string subTitle;
            public IList<RNode> children;          
        } 
          public class FlatObj //For Data format
        {
            public long Id;
            public long ParentId;
            public long Position;
            public string name;
            public string subTitle;
        }
        List<FlatObj> GlobalFlatObj = new List<FlatObj>();
        List<long> ParentIdList = new List<long>();
        long CurrentParentId=0;
        long CurrentPosition = 0;
    public List<FlatObj> FlatData(IList<RNode> HData) //Converting Heirarchical to Flat
    {
        foreach (RNode node in HData)
        {
            FlatObj ObjFlatObj = new FlatObj();
            ObjFlatObj.Id = node.ID;
            ObjFlatObj.name = node.name;
            ObjFlatObj.ParentId = CurrentParentId;
            ObjFlatObj.Position = CurrentPosition;
            GlobalFlatObj.Add(ObjFlatObj);
            if (node.children.Count > 0)
            {
                CurrentParentId = node.ID;
                ParentIdList.Add(node.ID);
                FlatData(node.children);
            }
            CurrentPosition++;
        }
        if (ParentIdList.Count > 0)
        {
            ParentIdList.RemoveAt(ParentIdList.Count - 1);
            if (ParentIdList.Count > 0)
                CurrentParentId = ParentIdList[ParentIdList.Count - 1];
            CurrentPosition = 0;
        }
        return GlobalFlatObj;
    }
    public dynamic Test(List<RNode> EmployeeHierarchy)
    {
        var HierarchyResult = FlatData(EmployeeHierarchy); //Calling
        return Ok(HierarchyResult);
    }

输入：

[
    {
    "$id": "1",
    "ID": 1,
    "name": "root",
    "subTitle": "root",
    "children": [
        {
            "$id": "2",
            "ID": 2,
            "name": "child 1",
            "subTitle": "child 1",
            "children": [
                {
                    "$id": "3",
                    "ID": 5,
                    "name": "grandchild",
                    "subTitle": "grandchild",
                    "children": []
                }]
        },                  
        {
            "$id": "4",
            "ID": 3,
            "name": "child 2",
            "subTitle": "child 2",
            "children": []
        },
        {
            "$id": "5",
            "ID": 4,
            "name": "child 3",
            "subTitle": "child 3",
            "children": []
        }       
    ]
    }
    ]

输出：

[
{
    "$id": "1",
    "Id": 1,
    "ParentId": 0,
    "Position": 0,
    "name": "root",
    "subTitle": null
},
{
    "$id": "2",
    "Id": 2,
    "ParentId": 1,
    "Position": 0,
    "name": "child 1",
    "subTitle": null
},
{
    "$id": "3",
    "Id": 5,
    "ParentId": 2,
    "Position": 0,
    "name": "grandchild",
    "subTitle": null
},
{
    "$id": "4",
    "Id": 3,
    "ParentId": 1,
    "Position": 1,
    "name": "child 2",
    "subTitle": null
},
{
    "$id": "5",
    "Id": 4,
    "ParentId": 1,
    "Position": 2,
    "name": "child 3",
    "subTitle": null
}

]