Question

我有一个自引用表，我需要将日期从表绑定到树视图用户控件。我使用BuildThree（）方法来获取子项。我的问题是如何使用我的View模型

获取父级，直到达到根父级

我的实体：

 public partial class Category
        {

            public Category()
            {
                this.children = new HashSet<Category>();
            }

            public int CategoryId { get; set; }
            public string CategoryName { get; set; }
            public Nullable<int> ParentCategoryId { get; set; }

            public virtual ICollection<Category> children { get; set; }
            public virtual Category Parent { get; set; }
        }

我的观点模型：

public class TreeViewModel
{
        public TreeViewModel()
        {
            this.children = new HashSet<TreeViewModel>();
        }

        public int id { get; set; }

        public string text { get; set; }

        public virtual TreeViewModel MyParent { get; set; }

        public virtual IEnumerable<TreeViewModel> children { get; set; }

    }

这是我用来生孩子的方法

   public IEnumerable<TreeViewModel> BuildThree(IEnumerable<Category> categories, int? parentCategoryId = null)
    {
        if (categories == null)
            return null;
        var result = categories.Select(c => new TreeViewModel()
        {     
            id = c.CategoryId,
            text = c.CategoryName,

            children = BuildThree(c.children, c.CategoryId)
        });
        return result;
    }





        Database1Entities db = new Database1Entities();
        var category = db.Categories.Find(id);

        TreeViewModel vm = new TreeViewModel();
        vm.id = category.CategoryId;
        vm.text = category.CategoryName;

        vm.children = BuildThree(category.children);

Answer 1

如果您只想找到填充MyParent属性的方法，那么必须对BuildThree方法进行少量更改。

public IEnumerable<TreeViewModel> BuildThree(IEnumerable<Category> categories, TreeViewModel parentCategory)
    {
        if (categories == null)
            return null;
        var result = new List<TreeViewModel>();
        foreach (var category in categories)
        {
           var treeViewModel = new TreeViewModel();
           treeViewModel.Id = category.CategoryId,
           treeViewModel.Text = category.CategoryName,
           treeViewModel.MyParent = parentCategory; 
           treeViewModel.Children= BuildThree(category.children,treeViewModel);
           result.Add(treeViewModel);   
        }
        return result;
    }

实体框架自引用表。如何让父母到达root

1 个答案: