Recursive Hierarchy - Recursive Query using Linq
c#, entity-framework, linq, recursion
Solution
While it is possible to use a recursive method here, you can traverse this tree structure using an explicit stack instead to avoid using the stack space, which isn't always sufficient for large tree structures. Such a method is also very nice as an iterator block, and iterator blocks are much more expensive when recursive than regular methods, so this will perform better as well:
public static IEnumerable<T> Traverse<T>(this IEnumerable<T> items,
Func<T, IEnumerable<T>> childSelector)
{
var stack = new Stack<T>(items);
while(stack.Any())
{
var next = stack.Pop();
yield return next;
foreach(var child in childSelector(next))
stack.Push(child);
}
}
Problem
I am using Entity Framework (version 6) to map to a recursive hierarchy and it maps nicely. My issue is that I want to recursively get ALL child nodes of a particular node in the hierarchy. I get the child nodes quite easily using Linq: ``` var recursiveList = db.ProcessHierarchyItems .Where(x => x.id == id) .SelectMany(x => x.Children); ``` Does anybody know of a clean implementation, that will recursively get all children?