How to map a 2D-Array to a collection of “array-objects” with automapper?

Question

I have a class that contains a 2D-Array and a class with a collection of ArrayValue objects (shown below). How can i map between those 2 classes?

class ArrayMap {
    int[,] map;
}

class CollectionMap {
    ICollection<ArrayValue> map;
}

class ArrayValue {
    int x;
    int y;
    int value;
}

Is it able to map these classes with Automapper or do I have to code my own mapping?

Answer 1

You can achieve this kind of custom mapping by implementing value converter :

public class CollectionMapConverter : IValueConverter<int[,], ICollection<ArrayValue>>
{
    public ICollection<ArrayValue> Convert(int[,] sourceMember, ResolutionContext context)
    {
        var collection = new List<ArrayValue>();

        for (var x = 0; x < sourceMember.GetLength(0); x++)
        {
            for (var y = 0; y < sourceMember.GetLength(1); y++)
            {
                collection.Add(new ArrayValue
                {
                    value = sourceMember[x, y],
                    x = x,
                    y = y,
                });
            }
        }

        return collection;
    }
}

then specify its usage when configurating map between ArrayMap and CollectionMap :

configuration.CreateMap<ArrayMap, CollectionMap>()
    .ForMember(collectionMap => collectionMap.map, options =>
    {
        options.ConvertUsing(new CollectionMapConverter());
    });

I assumed first dimension applies to a horizontal axis (X) and second one - to the vertical axis (Y). The current manner of reading the two-dimensional array is starting from the top left corner [0; 0] and going down (Y++), till the end of rows (Y), then stepping one column further (X++) and starting again the from the top (Y = 0). Repeat until the end of columns.

Eventually, mapping a two-dimensional int array shown below:

+------------------->
|                   X
|   +---+---+
|   | 1 | 4 |
|   +---+---+
|   | 2 | 5 |
|   +---+---+
|   | 3 | 6 |
|   +---+---+
|
|
v Y

will result in a collection of 6 ArrayValue elements:

If you would like to have other order, then you would have construct the for loops differently.