EF LINQ include nested entities [duplicate]

问题

This question already has an answer here:

Tree stucture table and entity framework (1 answer)

Closed 3 years ago.

I have multi-leveled entities with the following hierarchy: Parent-> RootChildren -> Children -> Children -> .....

Class Parent 
{
   public int Id {get; set;}
   public virtual Child RootChildren {get; set;}
}    
Class Child
{
   public virtual List<Child> Children {get; set;}
}

Now, I want to include entity which include all the child as nested way.

I tried the following but it didn't work:

var parents = dbContext.Parent 
                    .Where(p => p.Id == id)
                    .Select(r => r.RootChildren)
                    .Include(c => c.Children)
                    .ToList();

It gives me result for first children but does not include all the nested children present in the tree.

Any piece of advise or information would be highly appreciated. Thanks!

回答1:

You shouldn't try to apply Include after Select and perform Include hierarchical;

var parents = dbContext.Parent
    .Where(p => p.Id == id)
    .Include(c => c.RootChildren.Children)
    .Select(r => r.RootChildren)
    .ToList();

来源：https://stackoverflow.com/questions/48096194/ef-linq-include-nested-entities