Map object properties to dictionary on automapper - automapper

Question

I am trying to map an object to a dictionary in a way that each property will be a dictionary item.
Object with id and name -> dictionary with two items containing property name and value.
I know it is a simple thing, but I was not able to find a solution for it. Maybe it is something I am not understanding...
I receive the following error:
Unmapped members were found. Review the types and members below.
Add a custom mapping expression, ignore, add a custom resolver, or modify the source/destination type
For no matching constructor, add a no-arg ctor, add optional arguments, or map all of the constructor parameters
=======================================================================================================================================================================================================================================================================
Book -> Dictionary`2 (Destination member list)
Book -> System.Collections.Generic.Dictionary`2[[System.String, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.String, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]] (Destination member list)
Unmapped properties:
Keys
Values
Item
In the following code you can see my implementation:
using AutoMapper;
var book = new Book()
{
Id = 1,
Name = "A"
};
IMapper mapper = new Mapper(new MapperConfiguration(
config => config.CreateMap<Book, Dictionary<string, string>>()
.ConstructUsing((source, dest) => new Dictionary<string, string>()
{
{ "id", source.Id.ToString() },
{"name", source.Name}
})));
mapper.ConfigurationProvider.AssertConfigurationIsValid();
var bookData = new Dictionary<string, string>();
mapper.Map(book, bookData);
public class Book
{
public int Id { get; set; }
public string Name { get; set; }
}

Answer 1

As #Lucian mentioned in a comment, Automapper has built-in methods to convert object from/to dynamic, Dictionary<string, object>.
However, I think that there is an issue if you implement a converter to Dictionary<string, string>.
Hence, it is better to build a custom implementation for the conversion as below:
using System.Reflection;
using Newtonsoft.Json;
public static class DictionaryExtensions
{
public static Dictionary<string, string> ToDictionary<T>(this T src) where T : new()
{
Dictionary<string, string> result = new ();
PropertyInfo[] properties = typeof(T).GetProperties();
foreach (PropertyInfo prop in properties)
{
result.Add(prop.Name, prop.PropertyType == typeof(string)
? prop.GetValue(src)?.ToString()
: JsonConvert.SerializeObject(prop.GetValue(src)));
}
return result;
}
}
For caller:
var bookData = book.ToDictionary();
Demo # .NET Fiddle