fixed issue with datetime types in date filter

src/Reveal.Sdk.Dom/Core/Serialization/Converters/DateTimeConverter.cs

@@ -0,0 +1,49 @@
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using System;
+
+namespace Reveal.Sdk.Dom.Core.Serialization.Converters
+{
+    internal class DateTimeConverter : JsonConverter
+    {
+        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        {
+            if (value is DateTime dateTimeValue)
+            {
+                JObject jObject = new JObject
+                {
+                    ["_type"] = "date",
+                    ["value"] = dateTimeValue
+                };
+                jObject.WriteTo(writer);
+            }
+            else
+            {
+                throw new JsonSerializationException("Expected DateTime object.");
+            }
+        }
+
+        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        {
+            JObject jObject = JObject.Load(reader);
+            var type = jObject["_type"].Value<string>();
+            if (type == "date")
+            {
+                var value = jObject["value"];
+                if (value != null)
+                {
+                    return value.Value<DateTime>();
+                }
+                //todo: need to handle the option of XML date time which is a string
+                //this code logic can be found on line 248 of JsonUtility.cs in DataLayer.WPF
+            }
+
+            return null;
+        }
+
+        public override bool CanConvert(Type objectType)
+        {
+            return typeof(DateTime).IsAssignableFrom(objectType);
+        }
+    }
+}

src/Reveal.Sdk.Dom/Filters/Bindings/DashboardDateFilterBindingTarget.cs

@@ -1,10 +1,15 @@
-using Reveal.Sdk.Dom.Core.Constants;
+using Newtonsoft.Json;
+using Reveal.Sdk.Dom.Core.Constants;
 
 namespace Reveal.Sdk.Dom.Filters
 {
     public sealed class DashboardDateFilterBindingTarget : BindingTarget
     {
-        public string GlobalFilterFieldName { get; set; }
+        [JsonProperty("GlobalFilterId")]
+        public string DashboardFilterId { get; set; }
+
+        [JsonProperty("GlobalFilterFieldName")]
+        public string DashboardFilterFieldName { get; set; }
 
         public DashboardDateFilterBindingTarget()
         {

src/Reveal.Sdk.Dom/Filters/DashboardFilter.cs

@@ -10,5 +10,9 @@ public abstract class DashboardFilter : SchemaType
     {
         public string Id { get; set; } = Guid.NewGuid().ToString();
         public string Title { get; set; }
+
+        //todo: figure this out
+        [JsonProperty]
+        internal string CrossFilteringSourceWidgetId { get; set; }
     }
 }

src/Reveal.Sdk.Dom/Primitives/DateRange.cs

@@ -1,10 +1,15 @@
-using System;
+using Newtonsoft.Json;
+using Reveal.Sdk.Dom.Core.Serialization.Converters;
+using System;
 
 namespace Reveal.Sdk.Dom
 {
     public sealed class DateRange
     {
+        [JsonConverter(typeof(DateTimeConverter))]
         public DateTime? From { get; set; }
+
+        [JsonConverter(typeof(DateTimeConverter))]
         public DateTime? To { get; set; }
     }
 }