Fix criteria DateTimeOffset and DateTime JSON parsing

src/Serenity.Net.Data/Criteria/CriteriaJsonConverter.cs

@@ -126,7 +126,7 @@ private BaseCriteria Parse(JsonElement[] array)
                         throw new ArgumentNullException("item");
 
                     if (item.ValueKind == JsonValueKind.String)
-                        list.Add(item.GetString());
+                            list.Add(item.GetString());
                     else if (item.ValueKind == JsonValueKind.Number)
                         list.Add(item.GetDouble());
                     else if (item.ValueKind == JsonValueKind.True)

src/Serenity.Net.Entity/FieldTypes/DateTimeOffsetField.cs

@@ -36,6 +36,41 @@ public static DateTimeOffsetField Factory(ICollection<Field> collection, string
         return new DateTimeOffsetField(collection, name, caption, size, flags, getValue, setValue);
     }
 
+    /// <summary>
+    /// Converts the value.
+    /// </summary>
+    /// <param name="source">The source.</param>
+    /// <param name="provider">The provider.</param>
+    /// <returns></returns>
+    public override object ConvertValue(object source, IFormatProvider provider)
+    {
+        if (source is Newtonsoft.Json.Linq.JValue jValue)
+            source = jValue.Value;
+
+        if (source == null)
+            return null;
+
+        if (source is DateTime dt)
+            return dt;
+
+        if (source is DateTimeOffset dto)
+            return dto.DateTime;
+
+        if (source is string s)
+        {
+            if (DateTimeOffset.TryParse(s, provider, DateTimeStyles.None, out var dtOffset))
+                return dtOffset;
+
+            if (s.TryParseISO8601DateTime(out var dateTime))
+                return dateTime;
+
+            if (DateTime.TryParse(s, provider, DateTimeStyles.None, out dateTime))
+                return dateTime;
+        }
+
+        return Convert.ChangeType(source, typeof(DateTime), provider);
+    }
+
     /// <summary>
     /// Gets field value from a data reader.
     /// </summary>

src/Serenity.Net.Entity/FieldTypes/GenericValueField.cs

@@ -42,13 +42,11 @@ public override object ConvertValue(object source, IFormatProvider provider)
 
         if (source == null)
             return null;
-        else
-        {
-            if (source is TValue val)
-                return val;
 
-            return Convert.ChangeType(source, typeof(TValue), provider);
-        }
+        if (source is TValue val)
+            return val;
+
+        return Convert.ChangeType(source, typeof(TValue), provider);
     }
 
     /// <summary>