MatrixValueConverter.cs

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using MySite.Models.PropEditors;
using Umbraco.Core;
using Umbraco.Core.Models.PublishedContent;
using Umbraco.Core.PropertyEditors;

namespace MySite.Custom
{
    public class MatrixValueConverter :  IPropertyValueConverter
    {
        public bool IsConverter(IPublishedPropertyType propertyType)
        {
            return propertyType.EditorAlias.Equals("Custom.PropEditor");
        }

        public Type GetPropertyValueType(IPublishedPropertyType propertyType)
        {
            return typeof(Matrix);
        }

        public PropertyCacheLevel GetPropertyCacheLevel(IPublishedPropertyType propertyType)
        {
            return PropertyCacheLevel.Element;
        }

        public object ConvertSourceToIntermediate(IPublishedElement owner, IPublishedPropertyType propertyType, object source, bool preview)
        {
            if (source == null) return null;

            var sourceString = source.ToString();

            if (sourceString.DetectIsJson())
            {
                try
                {
                    var obj = JsonConvert.DeserializeObject<string[][]>(sourceString);
                    var matrix = new Matrix();
                    var rows = obj.Select(r => new Row { Cols = r.ToList()});
                    matrix.Rows = rows;
                    return matrix;
                }
                catch (Exception ex)
                {
                    return null;
                }
            }

            return null;
        }

        public bool? IsValue(object value, PropertyValueLevel level)
        {
            switch (level)
            {
                case PropertyValueLevel.Source:
                    return value != null;
                default:
                    throw new NotSupportedException($"Invalid level: {level}.");
            }
        }

        public object ConvertIntermediateToObject(IPublishedElement owner, IPublishedPropertyType propertyType, PropertyCacheLevel referenceCacheLevel, object inter, bool preview)
        {


            if (inter == null)
                return null;

            if (propertyType.Alias != null)
            {
                Matrix data;
                if (inter is Matrix)
                {
                    data = (Matrix)inter;
                    if (data != null)
                        return data;
                }
               
            }

            return inter;
        }

        public object ConvertIntermediateToXPath(IPublishedElement owner, IPublishedPropertyType propertyType, PropertyCacheLevel referenceCacheLevel, object inter, bool preview)
        {
            return null;
        }
    }
}