Get nested list of dynamic objects to be displayed as tree [duplicate]

Question

This question already has answers here:

How to build a tree from a flat structure? (21 answers)

Closed 6 years ago.

I have these two classes

public class Category
{
 public int Id { get; set; }
 public string Name { get; set; }
 public int? ParentId { get; set; }
}
public class CategoryVm
{
 public int Id { get; set; }
 public string Name { get; set; }
 public List<CategoryVm> SubCategories { get; set; }
}

and I have a list of the first class and I want to convert it to the second form to be displayed inside a tree view.

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Example input

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Example output

enter image description here

Answer 1

Here is the code that I used, and it worked properly

public List<CategoryVm> GetCategoriesTree(List<Category> categoriesList)
{
 var categoriesTree = categoriesList.Where(category => category.ParentCategoryId == null)
 .Select(category => new CategoryVm
 {
 Id = category.Id,
 Name = category.Name,
 SubCategories = new List<CategoryVm>()
 }).ToList();
 foreach (var category in categoriesTree)
 {
 FillSubCategories(category, categoriesList);
 }
 return categoriesTree;
}
private void FillSubCategories(CategoryVm categoryVm, List<Category> categoriesList)
{
 var subCategories = categoriesList.Where(category => category.ParentCategoryId == categoryVm.Id).ToList();
 if (subCategories.Any())
 {
 categoryVm.SubCategories = subCategories.Select(category => new CategoryVm
 {
 Id = category.Id,
 Name = category.Name,
 SubCategories = new List<CategoryVm>()
 }).ToList();
 foreach (var subCategory in categoryVm.SubCategories)
 {
 FillSubCategories(subCategory, categoriesList);
 }
 }
}