Easy Pretty Printing of C# Generic Collections

An extensible set of extension methods to pretty print (including contents of) collections in C#.

Normally when you print out a List<string> in C#, you get this:

System.Collections.Generic.List`1[System.String]

But with this simple library you get the contents of the List by calling listVar.ToStringExt():

[one, two, three]

The library is easy to use and expand for generic collections with more complex types.

Read about the technical details and drawbacks of this approach in my blog post (TODO link).

Full Example

Here is an example program included in this repository along with its output.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

using NoSuchStudio.Common;

namespace printext
{
    class Program
    {
        static void Main(string[] args)
        {
           // list
            Console.WriteLine("flat list");
            var strList = new List<string>() {"one", "two", "three"};
            Console.WriteLine("ToString: " + strList.ToString());
            Console.WriteLine("ToStringExt: " + strList.ToStringExt());
            Console.WriteLine("");

            // list of list
            Console.WriteLine("List of lists");
            var listOfLists = new List<List<string>>() { new List<string>() {"one", "two"}, new List<string>() {"three", "four"}};
            Console.WriteLine("ToString: " + listOfLists.ToString());
            Console.WriteLine("ToStringExt: " + listOfLists.ToStringExt());
            Console.WriteLine("");

            // list of list of list
            Console.WriteLine("List of Lists of Lists");
            var listOfListsOfLists = new List<List<List<string>>>() {
                new List<List<string>>() { new List<string>() {"one", "two"}, new List<string>() {"three", "four"}},
                new List<List<string>>() { new List<string>() {"five", "six"}, new List<string>() {"seven", "eight"}}};
            Console.WriteLine("ToString: " + listOfListsOfLists);
            Console.WriteLine("ToStringExt: " + listOfListsOfLists.ToStringExt());
            Console.WriteLine("");

            // dictionary
            Console.WriteLine("Dictionary");
            var flatDic = new Dictionary<int, string>() {
                [1] = "one",
                [2] = "two"
            };
            Console.WriteLine("ToString: " + flatDic);
            Console.WriteLine("ToStringExt: " + flatDic.ToStringExt());
            Console.WriteLine("");

            // dictionary of dictionary
            Console.WriteLine("Dictionary of Dictionaries");
            var dic2 = new Dictionary<int, Dictionary<string, string>>() {
                [1] = new Dictionary<string, string>() {
                    ["one"] = "first",
                    ["two"] = "second"
                },
                [2] = new Dictionary<string, string>() {
                    ["three"] = "third",
                    ["four"] = "forth"
                }
            };
            Console.WriteLine("ToString: " + dic2);
            Console.WriteLine("ToStringExt: " + dic2.ToStringExt());
            Console.WriteLine("");

            // dictionary of list
            Console.WriteLine("Dictionary of Lists");
            var dicOfList = new Dictionary<int, List<string>>() {
                [1] = new List<string>() {"one", "two"},
                [2] = new List<string>() {"three", "four"},
            };
            Console.WriteLine("ToString: " + dicOfList);
            Console.WriteLine("ToStringExt: " + dicOfList.ToStringExt());
            Console.WriteLine("");

            // list of dictionary
            Console.WriteLine("List of Dictionaries");
            var listOfDic = new List<Dictionary<int, string>>() {
                new Dictionary<int, string>() {
                    [1] = "one",
                    [2] = "two"
                },
                new Dictionary<int, string>() {
                    [3] = "three",
                    [4] = "four"
                }
            };
            Console.WriteLine("ToString: " + listOfDic);
            Console.WriteLine("ToStringExt: " + listOfDic.ToStringExt());
            Console.WriteLine("");

            // HashSet
            Console.WriteLine("HashSet");
            var hashSet = new HashSet<string>() {"one", "two", "three"};
            Console.WriteLine("ToString: " + hashSet.ToString());
            Console.WriteLine("ToStringExt: " + hashSet.ToStringExt());
            Console.WriteLine("");
        }
    }
}

Output:

hk1ll3r/CSharp-Collection-Print-Generics

Easy Pretty Printing of C# Generic Collections

Full Example