类型加载序列化期间的异常

Question

当我尝试在 .NET Core 项目(面向 2.2)中的表达式树上打开自定义可视化工具时，出现以下异常：

自定义可视化工具组件在调试过程中引发了类型为"System.TypeLoadException"的未处理异常。

无法从程序集"mscorlib， Version=4.0.0.0， Culture=neutral， PublicKeyToken=b77a5c561934e089"加载类型"System.Runtime.CompilerServices.IsReadOnlyAttribute"。

以下代码(从问题末尾的堆栈跟踪派生)似乎具有相同的问题：

// using System;
// using System.IO;
// using System.Runtime.Serialization.Formatters.Binary;
var stream = File.Create(Path.GetTempFileName());
var formatter = new BinaryFormatter();
var data = new VisualizerData(expr); // serialized class with information about a given expression tree
formatter.Serialize(stream, data); // fails with the same exception

当代码在 .NET Core 项目中运行时，但使用引用的 .NET Framework 程序集(面向 4.7.2)中的类 (VisualizerData);该程序集具有对 WPF 程序集的引用。

如何调试此问题？可能是什么原因造成的？

请注意，这里没有任何反序列化;这一切都是在启动序列化时进行的。

VisualizerDataObjectSource.TransferData(Object target, Stream incomingData, Stream outgoingData) in VisualizerDataObjectSource.cs:line 9的源代码

---

堆栈跟踪：

at System.ModuleHandle.ResolveType(RuntimeModule module, Int32 typeToken, IntPtr* typeInstArgs, Int32 typeInstCount, IntPtr* methodInstArgs, Int32 methodInstCount, ObjectHandleOnStack type)
at System.ModuleHandle.ResolveTypeHandleInternal(RuntimeModule module, Int32 typeToken, RuntimeTypeHandle[] typeInstantiationContext, RuntimeTypeHandle[] methodInstantiationContext)
at System.Reflection.RuntimeModule.ResolveType(Int32 metadataToken, Type[] genericTypeArguments, Type[] genericMethodArguments)
at System.Reflection.CustomAttribute.FilterCustomAttributeRecord(CustomAttributeRecord caRecord, MetadataImport scope, Assembly& lastAptcaOkAssembly, RuntimeModule decoratedModule, MetadataToken decoratedToken, RuntimeType attributeFilterType, Boolean mustBeInheritable, Object[] attributes, IList derivedAttributes, RuntimeType& attributeType, IRuntimeMethodInfo& ctor, Boolean& ctorHasParameters, Boolean& isVarArg)
at System.Reflection.CustomAttribute.IsCustomAttributeDefined(RuntimeModule decoratedModule, Int32 decoratedMetadataToken, RuntimeType attributeFilterType, Int32 attributeCtorToken, Boolean mustBeInheritable)
at System.Reflection.CustomAttribute.IsDefined(RuntimeMethodInfo method, RuntimeType caType, Boolean inherit)
at System.Runtime.Serialization.SerializationEvents.GetMethodsWithAttribute(Type attribute, Type t)
at System.Runtime.Serialization.SerializationEvents..ctor(Type t)
at System.Runtime.Serialization.SerializationEventsCache.<>c.<GetSerializationEventsForType>b__1_0(Type type)
at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
at System.Runtime.Serialization.SerializationEventsCache.GetSerializationEventsForType(Type t)
at System.Runtime.Serialization.SerializationObjectManager.RegisterObject(Object obj)
at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder)
at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Write(WriteObjectInfo objectInfo, NameInfo memberNameInfo, NameInfo typeNameInfo)
at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.WriteArrayMember(WriteObjectInfo objectInfo, NameInfo arrayElemTypeNameInfo, Object data)
at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.WriteArray(WriteObjectInfo objectInfo, NameInfo memberNameInfo, WriteObjectInfo memberObjectInfo)
at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Write(WriteObjectInfo objectInfo, NameInfo memberNameInfo, NameInfo typeNameInfo)
at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, BinaryFormatterWriter serWriter, Boolean fCheck)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Boolean check)
at ExpressionTreeVisualizer.VisualizerDataObjectSource.TransferData(Object target, Stream incomingData, Stream outgoingData) in C:UsersSpitzsourcereposzspitzExpressionToStringVisualizer.SharedVisualizerDataObjectSource.cs:line 9
at Microsoft.VisualStudio.DebuggerVisualizers.DebuggeeSide.Impl.ClrCustomVisualizerDebuggeeHost.TransferData(Object visualizedObject, Byte[] uiSideData)

Answer 1

如您所见，以下消息引用了 NET Framework 4.0 元素：

无法从程序集"mscorlib， Version=4.0.0.0， Culture=neutral， PublicKeyToken=b77a5c561934e089"加载类型"System.Runtime.CompilerServices.IsReadOnlyAttribute"。

您可以使用的最大 NetFramework 目标由此元素定义。

Answer 2

序列化在引用的 .NET Framework 程序集中定义的值类型似乎是问题的根源。

使用以下方法：

static (bool success, string failPath, string errorMessage) CanSerialize(object o, string path = "") {
var formatter = new BinaryFormatter();
using (var stream = File.Create(Path.GetTempFileName())) {
return CanSerialize(o, path, formatter, stream);
}
}
static (bool success, string failPath, string errorMessage) CanSerialize(object o, string path, BinaryFormatter formatter, Stream stream) {
if (o == null) { return (false, path, "Null object"); }
string msg;
var t = o.GetType();
if (t.IsPrimitive || t == typeof(string)) { return (true, path, null); }
try {
formatter.Serialize(stream, o);
return (true, path, null);
} catch (Exception ex) {
msg = ex.Message;
}
List<(string, object)> values;
if (t.IsArray) {
values = (o as IEnumerable).ToObjectList()
.Select((x, index) => ($"[{index}]", x))
.Where(x => x.Item2 != null)
.ToList();
} else {
values = t.GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
.Where(fld => !fld.IsStatic)
.Select(fld => ($".{fld.Name}", fld.GetValue(o)))
.Where(x => x.Item2 != null)
.ToList();
}
foreach (var (name, value) in values) {
var ret = CanSerialize(value, path + name, formatter, stream);
if (!ret.success) { return ret; }
}
return (false, path, msg);
}

以下struct定义：

[Serializable]
public struct EndNodeData {
public string Closure { get; set; }
public string Name { get; set; }
public string Type { get; set; }
public string Value { get; set; }
}

以下代码：

var endnodeData = new EndNodeData {
Closure = null,
Name = null,
Type = "int",
Value = "5"
};
Console.WriteLine(CanSerialize(endnodeData));

打印输出：

(False， 无法从程序集"mscorlib， Version=4.0.0.0， Culture=neutral， PublicKeyToken=b77a5c561934e089"加载类型"System.Runtime.CompilerServices.IsReadOnlyAttribute"。

问题似乎出在这种特定类型或一般值类型上。