使用 Automapper 从 Object List 隐藏到 2D Array 属性

Question

I am trying to convert an object list to a 2D Array property of another object using AutoMapper. This is an attempt to create GeoJson format like response.

Source Type

public class GeoCoordinateEntity
{
   public double Latitude { get; set; }
   public double Longitude  { get; set; }
}

Target Type

public class GeoEvent
{
   // Enum which in this case will be always Maps to LineString.
   public GeometryType GeometryType { get; set; }
   // Trying to Map this format??....
   public double[,] Coordinates { get; set; }
}

I get get IEnumerable and trying to map it to the Coordinates property of GeoEvent. Here is where I am struggling.

 CreateMap<IEnumerable<GeoCoordinateEntity>, GeoEvent>()
    .ForMember(
        dest => dest.GeometryType,
        opt => opt.MapFrom(src => GeometryType.LineString))
    .ForMember(
        dest => dest.Coordinates,
        opt => opt.MapFrom(src => /* Need Help */ ));

Can someone help me or point me in the right direction?

Answer 1

Convert the source to IEnumerable<IEnumerable<double>> and then write an extension method to convert it to 2D Array.

 CreateMap<IEnumerable<GeoCoordinateEntity>, GeoEvent>()
        .ForMember(dest => dest.Coordinates, opt => opt.MapFrom(source => 
        source.Select(prop => new List<double>
        {
            prop.Latitude,
            prop.Longitude
        })
        .To2DArray()));

Extension Method to Create Two Dimensional Array

static class EnumerableExtensions
{
    public static T[,] To2DArray<T>(this IEnumerable<IEnumerable<T>> source)
    {
        var data = source
            .Select(x => x.ToArray())
            .ToArray();

        var res = new T[data.Length, data.Max(x => x.Length)];
        for (var i = 0; i < data.Length; ++i)
        {
            for (var j = 0; j < data[i].Length; ++j)
            {
                res[i, j] = data[i][j];
            }
        }

        return res;
    }
}