创建侧载用UWP发布应用包时遇空引用异常错误求助

Problem Description #

When attempting to create a sideloaded release package for my UWP app, I'm hitting a NullReferenceException from the Net Native compiler during the serialization assembly generation step. Here's the full error output:

1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : System.NullReferenceException: Object reference not set to an instance of an object.
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at System.Xml.Serialization.XmlSerializationWriterCodeGen.FindXmlnsIndex(MemberMapping[] members)
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at System.Xml.Serialization.XmlSerializationWriterCodeGen.WriteStructMethod(StructMapping mapping)
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at System.Xml.Serialization.XmlSerializationWriterCodeGen.GenerateMethod(TypeMapping mapping)
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at System.Xml.Serialization.XmlSerializationCodeGen.GenerateReferencedMethods()
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at System.Xml.Serialization.XmlSerializationWriterCodeGen.GenerateEnd()
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at System.Xml.Serialization.TempAssembly.GenerateAssembly(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, Evidence evidence, XmlSerializerCompilerParameters parameters, Hashtable assemblies, String outputDir, IEnumerable 1 referenceDirectories, String intermediateDir, Boolean loadAssembly)
1>C:\Program Files (x86)\MSBuild\Microsoft\.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at System.Xml.Serialization.XmlSerializer.GenerateSerializer(Type[] types, XmlMapping[] mappings, CompilerParameters parameters, String outputDir, IEnumerable 1 referenceDirectories, String intermediateDir, Boolean loadAssembly)
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at System.Xml.Serialization.XmlSerializer.GenerateSerializer(Type[] types, String outputDir, IEnumerable 1 referenceDirectories, String intermediateDir, List 1 wcfSerializers, Boolean loadAssembly)
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : at SerializationAssemblyGenerator.Program.Main(String[] args)
1>C:\Program Files (x86)\MSBuild\Microsoft.NetNative\x64\ilc\IlcInternals.targets(936,5): error : Internal compiler error: One or more errors occurred.

My app's Package.appxmanifest content is as follows:

<?xml version="1.0" encoding="utf-8"?>
<Package xmlns="http://schemas.microsoft.com/appx/manifest/foundation/windows10" xmlns:mp="http://schemas.microsoft.com/appx/2014/phone/manifest" xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10" IgnorableNamespaces="uap mp">
<Identity Name="XXXXXXXXXX" Publisher="XXXXXXXXXX" Version="1.0.4.0" />
<mp:PhoneIdentity PhoneProductId="XXXXXXXXXX" PhonePublisherId="XXXXXXXXXX" />
<Properties>
<DisplayName>XXXXXXXXXX</DisplayName>
<PublisherDisplayName>XXXXXXXXXX</PublisherDisplayName>
<Logo>Assets\StoreLogo.png</Logo>
</Properties>
<Dependencies>
<TargetDeviceFamily Name="Windows.Universal" MinVersion="10.0.0.0" MaxVersionTested="10.0.0.0" />
</Dependencies>
<Resources>
<Resource Language="x-generate" />
</Resources>
<Applications>
<Application Id="App" Executable="$targetnametoken$.exe" EntryPoint="XXXXXXXXXX.App">
<uap:VisualElements DisplayName="XXXXXXXXXX" Square150x150Logo="Assets\Square150x150Logo.png" Square44x44Logo="Assets\Square44x44Logo.png" Description="XXXXXXXXXX" BackgroundColor="transparent">
<uap:DefaultTile Wide310x150Logo="Assets\Wide310x150Logo.png">
</uap:DefaultTile>
<uap:SplashScreen Image="Assets\SplashScreen.png" />
</uap:VisualElements>
</Application>
</Applications>
<Capabilities>
<Capability Name="internetClient" />
<uap:Capability Name="phoneCall" />
<uap:Capability Name="picturesLibrary" />
<uap:Capability Name="userAccountInformation" />
<DeviceCapability Name="location" />
<DeviceCapability Name="proximity" />
<DeviceCapability Name="webcam" />
</Capabilities>
</Package>

I'm looking to understand what's causing this error and how to resolve it.

Solution & Root Cause Analysis #

Looking at the error stack trace, the crash happens in XmlSerializationWriterCodeGen.FindXmlnsIndex—this points to an issue when the Net Native compiler tries to generate an XML serialization assembly for your app's types. Here are the most likely causes and fixes:

1. Invalid XML Serialization Attributes in Your Code #

The NullReferenceException suggests that one of your data types (marked for XML serialization) has a member with a null or improperly configured XML namespace reference. For example:

• A class member using XmlElementAttribute or XmlRootAttribute with a Namespace property set to null
• Conflicting namespace configurations across related serialized types

Fix: Audit all types in your project that use XmlSerializer attributes. Ensure every namespace reference is either a valid string or omitted entirely (instead of being set to null).

2. Disable Net Native XML Serialization Optimization #

The Net Native compiler attempts to pre-generate serialization assemblies for performance, but this can sometimes hit edge cases like this. You can disable this optimization to let the runtime handle serialization instead:

Fix: Edit your UWP project file (.csproj) and add the following property inside the <PropertyGroup> section:

<EnableXmlSerializerOptimization>false</EnableXmlSerializerOptimization>

3. Outdated Target SDK Version #

Your manifest sets MinVersion and MaxVersionTested to 10.0.0.0, which is extremely old (the initial Windows 10 release). Newer SDK versions include fixes for Net Native compiler bugs.

Fix: Update the TargetDeviceFamily values to a more recent version, e.g.:

<TargetDeviceFamily Name="Windows.Universal" MinVersion="10.0.17763.0" MaxVersionTested="10.0.22621.0" />

Make sure your project is targeting a matching SDK version in Visual Studio's project properties.

4. Corrupted Build Cache #

Sometimes leftover intermediate build files can cause strange compiler errors.

Fix: Delete the bin and obj folders in your project directory, then clean and rebuild the solution from scratch.

5. Conflicting Serialization Libraries #

If your app uses both XmlSerializer and other serialization frameworks (like DataContractSerializer or third-party libraries), there might be conflicts during the Net Native compilation step.

Fix: Verify that all serialization-related code is consistent, and ensure you're not mixing incompatible serialization approaches for the same types.

内容的提问来源于stack exchange，提问作者Paul Diston