我正在使用SQL Server和Entity Framework。在我的数据库中,我有以下数据:
ID | Name | ParentID
1 | Fire | null
2 | Fire2 | 1
3 | Fire3 | 2
4 | Blast | 2
5 | Water | null
6 | Water2 | 5
7 | WaterX | 5
我不会获得大量数据,因此从数据库中一次检索所有内容是完全可以接受的。
我想检索这些数据并在屏幕上显示为"树"。
Fire
Fire2
Fire3 Blast
Water
Water2 WaterX
我该怎么做?我应该创建某种递归来呈现它吗?我应该以某种方式将列表转换为IGrouping吗?
我无法将平面列表转换为可以在屏幕上分层渲染的内容,我该怎么做?
答案 0 :(得分:1)
如果您可以在您的类中添加另一个属性,其中包含以下子项:
public class Thing
{
public Thing()
{
Things = new List<Thing>();
}
public int Id { get; set; }
public string Name { get; set; }
public int? ParentId { get; set; }
public List<Thing> Things { get; set; }
}
然后您可以轻松地将项目分组给他们的父母:
var things = new List<Thing>
{
new Thing { Id = 1, Name = "Fire", ParentId = null },
new Thing { Id = 2, Name = "Fire2", ParentId = 1 },
new Thing { Id = 3, Name = "Fire3", ParentId = 2 },
new Thing { Id = 4, Name = "Blast", ParentId = 2},
new Thing { Id = 5, Name = "Water", ParentId = null },
new Thing { Id = 6, Name = "Water2", ParentId = 5 },
new Thing { Id = 7, Name = "Waterx", ParentId = 6 }
};
var groupedThings = new List<Thing>();
foreach (var thing in things)
{
if (thing.ParentId != null)
{
things.First(t => t.Id == thing.ParentId).Things.Add(thing);
}
else
{
groupedThings.Add(thing);
}
}
groupedThings.Dump();
答案 1 :(得分:1)
这是我所知道的最简单方法:
var things = new []
{
new { Id = 1, Name = "Fire", ParentId = (int?)null },
new { Id = 2, Name = "Fire2", ParentId = (int?)1 },
new { Id = 3, Name = "Fire3", ParentId = (int?)2 },
new { Id = 4, Name = "Blast", ParentId = (int?)2 },
new { Id = 5, Name = "Water", ParentId = (int?)null },
new { Id = 6, Name = "Water2", ParentId = (int?)5 },
new { Id = 7, Name = "Waterx", ParentId = (int?)5 }
};
var tree = things.ToLookup(x => x.ParentId, x => new { x.Id, x.Name });
树看起来像这样:
现在应该很容易呈现。