Multi Level Loop with Customization

Question

i have hard time to achieve some expected result with infinity loop. I want to create multi level category with some customization in result.

Source Data

   ID    |      Name      | ParentID |
---------+----------------+----------+
   1     |   Category 1   |    0     |
   2     |   Category 2   |    1     |
   3     |   Category 3   |    1     |
   4     |   Category 4   |    3     |
   5     |   Category 5   |    3     |
   6     |   Category 6   |    4     |

Result i expected in JSON

[
{"ID":1,"Name":"Category 1"},
{"ID":2,"Name":"Category 1/Category 2"},
{"ID":3,"Name":"Category 1/Category 3"},
{"ID":4,"Name":"Category 1/Category 3/Category 4"},
{"ID":5,"Name":"Category 1/Category 3/Category 5"},
{"ID":6,"Name":"Category 1/Category 3/Category 4/Category 6"}
]

How to get expected result using C#. I hope i can get any advice here.

What have you tried? What was the problem with your approach? How can we help to improve your attempt? (edit that in the question or do more research) — Tatranskymedved, Dec 15 '20 at 11:13

score 0 · Answer 1 · answered Dec 15 '20 at 11:36

Use a recursive algorithm :

    class Program
    {
        static DataTable dt = new DataTable();
        static List<string> results = new List<string>();
 
        static void Main(string[] args)
        {
            dt.Columns.Add("ID", typeof(int));
            dt.Columns.Add("Name", typeof(string));
            dt.Columns.Add("ParentID", typeof(int));

            dt.Rows.Add(new object[] { 1, "Category 1", 0});
            dt.Rows.Add(new object[] { 2, "Category 2", 1});
            dt.Rows.Add(new object[] { 3, "Category 3", 1});
            dt.Rows.Add(new object[] { 4, "Category 4", 3});
            dt.Rows.Add(new object[] { 5, "Category 5", 3});
            dt.Rows.Add(new object[] { 6, "Category 6", 4});

            PrintRecursive(0, "");
            foreach (string result in results)
            {
                Console.WriteLine(result);
            }
            Console.ReadLine();

        }
        static void PrintRecursive(int parent, string name)
        {
            DataRow[] rows = dt.AsEnumerable().Where(x => x.Field<int>("ParentID") == parent).ToArray();
            if (rows.Length != 0)
            {
                foreach (DataRow row in rows)
                {
                    int child = row.Field<int>("ID");
                    string childStr = row.Field<string>("Name");
                    results.Add(string.Format("\"ID\":{0},\"Name\":\"{1}\"", child, name));
                    PrintRecursive(child, name + "/" + childStr);
                }
            }
        }
    }

Multi Level Loop with Customization

1 Answers1