"Xamarin.Forms with Web Assembly" example. Failed to process received message: Newtonsoft.Json.JsonSerializationException

[jinek]

Send {"m":"event","id":"⦙5","k":"click","v":{"offsetX":531,"offsetY":14}} ooui.js:12:24
Failed to process received message: Newtonsoft.Json.JsonSerializationException: Error getting value from 'MessageType' on 'Ooui.Message'. ---> System.NullReferenceException: Object reference not set to an instance of an object. mono.js:1:34956
at System.Linq.Expressions.Interpreter.LightLambda.MakeRunDelegateCtor (System.Type delegateType) <0x24c5c68 + 0x00294> in <925a8f26f6cb48aba56b19a0300004fc>:0 mono.js:1:34956
at System.Linq.Expressions.Interpreter.LightLambda.GetRunDelegateCtor (System.Type delegateType) <0x24c5568 + 0x00048> in <925a8f26f6cb48aba56b19a0300004fc>:0 mono.js:1:34956
at System.Linq.Expressions.Interpreter.LightLambda.MakeDelegate (System.Type delegateType) <0x24c53d8 + 0x0000e> in <925a8f26f6cb48aba56b19a0300004fc>:0 mono.js:1:34956
at System.Linq.Expressions.Interpreter.LightDelegateCreator.CreateDelegate (System.Runtime.CompilerServices.IStrongBox[] closure) <0x24bd9b0 + 0x00028> in <925a8f26f6cb48aba56b19a0300004fc>:0 mono.js:1:34956
at System.Linq.Expressions.Interpreter.LightDelegateCreator.CreateDelegate () <0x24bd840 + 0x0000a> in <925a8f26f6cb48aba56b19a0300004fc>:0 mono.js:1:34956
at System.Linq.Expressions.Expression1[TDelegate].Compile (System.Boolean preferInterpretation) <0x2615348 + 0x0001c> in <925a8f26f6cb48aba56b19a0300004fc>:0 mono.js:1:34956 at System.Linq.Expressions.Expression1[TDelegate].Compile () <0x2615310 + 0x0000a> in <925a8f26f6cb48aba56b19a0300004fc>:0 mono.js:1:34956
at Newtonsoft.Json.Utilities.ExpressionReflectionDelegateFactory.CreateGet[T] (System.Reflection.FieldInfo fieldInfo) <0x260b138 + 0x000ba> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.Utilities.ReflectionDelegateFactory.CreateGet[T] (System.Reflection.MemberInfo memberInfo) <0x260ad48 + 0x00050> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.Serialization.ExpressionValueProvider.GetValue (System.Object target) <0x260ab40 + 0x0002a> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
--- End of inner exception stack trace --- mono.js:1:34956
at Newtonsoft.Json.Serialization.ExpressionValueProvider.GetValue (System.Object target) <0x260ab40 + 0x0008a> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue (Newtonsoft.Json.Serialization.JsonProperty property, Newtonsoft.Json.JsonConverter propertyConverter, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerProperty, Newtonsoft.Json.JsonReader reader, System.Object target) <0x2609ca0 + 0x000a2> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject (System.Object newObject, Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonObjectContract contract, Newtonsoft.Json.Serialization.JsonProperty member, System.String id) <0x25df848 + 0x003fa> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject (Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, System.Object existingValue) <0x25ca080 + 0x0029e> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, System.Object existingValue) <0x25c8fa0 + 0x000ce> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType, System.Boolean checkAdditionalContent) <0x238a7c0 + 0x001aa> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.JsonSerializer.DeserializeInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType) <0x237dd28 + 0x000b0> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.JsonSerializer.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType) <0x237d648 + 0x0001c> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.JsonConvert.DeserializeObject (System.String value, System.Type type, Newtonsoft.Json.JsonSerializerSettings settings) <0x235f888 + 0x0006c> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (System.String value, Newtonsoft.Json.JsonSerializerSettings settings) <0x235f068 + 0x00020> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (System.String value) <0x235efa8 + 0x0000a> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 mono.js:1:34956
at Ooui.WebAssemblySession.ReceiveMessageJson (System.String json) <0x235ec00 + 0x0000e> in :0 mono.js:1:34956
Event
Object { m: "event", id: "⦙5", k: "click", v: {…} }

[alexeystrakh]

Getting the same error here when trying to test Ooui.Wasm + Forms published as a static website. The static page is loaded and initial Xamarin.Forms layout is rendered but button click doesn't work with the following error printed to the console:

https://mobcatsamplesstorage.blob.core.windows.net/oouisamples/index.html

Failed to process received message: Newtonsoft.Json.JsonSerializationException: Error getting value from 'MessageType' on 'Ooui.Message'. ---> System.NullReferenceException: Object reference not set to an instance of an object.
mono.js:1   at System.Linq.Expressions.Interpreter.LightLambda.MakeRunDelegateCtor (System.Type delegateType) <0x255c030 + 0x00294> in <f6e39cacb6aa420b89273d00af75095c>:0 
mono.js:1   at System.Linq.Expressions.Interpreter.LightLambda.GetRunDelegateCtor (System.Type delegateType) <0x255b930 + 0x00048> in <f6e39cacb6aa420b89273d00af75095c>:0 
mono.js:1   at System.Linq.Expressions.Interpreter.LightLambda.MakeDelegate (System.Type delegateType) <0x2553740 + 0x0000e> in <f6e39cacb6aa420b89273d00af75095c>:0 
mono.js:1   at System.Linq.Expressions.Interpreter.LightDelegateCreator.CreateDelegate (System.Runtime.CompilerServices.IStrongBox[] closure) <0x2552e80 + 0x00028> in <f6e39cacb6aa420b89273d00af75095c>:0 
mono.js:1   at System.Linq.Expressions.Interpreter.LightDelegateCreator.CreateDelegate () <0x2552d10 + 0x0000a> in <f6e39cacb6aa420b89273d00af75095c>:0 
mono.js:1   at System.Linq.Expressions.Expression`1[TDelegate].Compile (System.Boolean preferInterpretation) <0x26ae6d0 + 0x0001c> in <f6e39cacb6aa420b89273d00af75095c>:0 
mono.js:1   at System.Linq.Expressions.Expression`1[TDelegate].Compile () <0x26ae698 + 0x0000a> in <f6e39cacb6aa420b89273d00af75095c>:0 
mono.js:1   at Newtonsoft.Json.Utilities.ExpressionReflectionDelegateFactory.CreateGet[T] (System.Reflection.FieldInfo fieldInfo) <0x26a2a30 + 0x000ba> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.Utilities.ReflectionDelegateFactory.CreateGet[T] (System.Reflection.MemberInfo memberInfo) <0x26a2640 + 0x00050> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.Serialization.ExpressionValueProvider.GetValue (System.Object target) <0x26a2438 + 0x0002a> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1    --- End of inner exception stack trace ---
mono.js:1   at Newtonsoft.Json.Serialization.ExpressionValueProvider.GetValue (System.Object target) <0x26a2438 + 0x0008a> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue (Newtonsoft.Json.Serialization.JsonProperty property, Newtonsoft.Json.JsonConverter propertyConverter, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerProperty, Newtonsoft.Json.JsonReader reader, System.Object target) <0x26a1598 + 0x000a2> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject (System.Object newObject, Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonObjectContract contract, Newtonsoft.Json.Serialization.JsonProperty member, System.String id) <0x2677bb0 + 0x003fa> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject (Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, System.Object existingValue) <0x266dd28 + 0x0029e> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, System.Object existingValue) <0x2662ed8 + 0x000ce> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType, System.Boolean checkAdditionalContent) <0x2426368 + 0x001aa> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.JsonSerializer.DeserializeInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType) <0x24180c0 + 0x000b0> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.JsonSerializer.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType) <0x24179e0 + 0x0001c> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.JsonConvert.DeserializeObject (System.String value, System.Type type, Newtonsoft.Json.JsonSerializerSettings settings) <0x23fd600 + 0x0006c> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (System.String value, Newtonsoft.Json.JsonSerializerSettings settings) <0x23fcde0 + 0x00020> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (System.String value) <0x23fcd20 + 0x0000a> in <9b6398b0b3ae4afdb586fd62eda2ead4>:0 
mono.js:1   at Ooui.WebAssemblySession.ReceiveMessageJson (System.String json) <0x23fc978 + 0x0000e> in <9bb9d93261e543f6adb8cd3fa7c65a76>:0 

A few additional test to isolate the issue:

1. Running the same code using a local server (phyton server.py) reproduces the same issue, so this is not related to the publishing
2. Running the same code without Ooui.Wasm (dotnet run mycoolapp.dll) works fine and the button click handler is properly executed (on the server side)

[alexeystrakh]

By the confirmation from the author, this is a known issue and the Ooui SDK to be adopted for .NET 6