Question

When I try to run the following code (two separated assemblies)

ClassLibrary.cs

public interface ITest
{
}

Program.cs

using System;

public class TestClass
{
    public void Test<T>(T x) where T : ITest { }
}

static class Program
{ 
    static void Main(string[] args)         
    {
        new System.Xml.Serialization.XmlSerializer(typeof(TestClass));
    }
}

Compiled in Windows 7 64-Bit using the following commands:

c:\Windows\Microsoft.NET\Framework\v2.0.50727\csc /target:library ClassLibrary.cs

c:\Windows\Microsoft.NET\Framework\v2.0.50727\csc /reference:ClassLibrary.dll Program.cs

I’m getting the this exception:

System.InvalidOperationException: Unable to generate a temporary class
(result=1). error CS0012: The type
ITest is defined in an assembly that
is not referenced. You must add a
reference to assembly ClassLibrary,
Version=0.0.0.0, Culture=neutral,
PublicKeyToken=null hinzu.

at
System.Xml.Serialization.Compiler.Compile(Assembly
parent, String ns,
XmlSerializerCompilerParameters
xmlParameters, Evidence evidence)
at
System.Xml.Serialization.TempAssembly.GenerateAssembly(XmlMapping[]
xmlMappings, Type[] types, String
defaultNamespace, Evidence evidence,
XmlSerializerCompilerParameters
parameters, Assembly assembly,
Hashtable assemblies) at
System.Xml.Serialization.TempAssembly..ctor(XmlMapping[]
xmlMappings, Type[] types, String
defaultNamespace, String location,
Evidence evidence) at
System.Xml.Serialization.XmlSerializer.GenerateTempAssembly(XmlMapping
xmlMapping, Type type, String
defaultNamespace) at
System.Xml.Serialization.XmlSerializer..ctor(Type
type, String defaultNamespace) at
Program.Main(String[] args)

Removing the where T : ITest from TestClass or not using generics at all (e.g. using public void Test(ITest x)) will prevent the exception from being thrown but I need this construct in my real application.

Do anybody understand why the XmlSerializer is unable to handle the where constraint?

Answer 1

I think you are out of luck. Here’s the response from Microsoft about this issue:

Thank you for submitting this issue.
Unfortunately, we have decided that it
will not be addressed because the risk
of the fix outweighs its benefit. By
the time the next opportunity to make
this change comes about, the hope is
that the new serialization
technologies in a future version of
the Windows Communication Foundation
will address your scenario. If this
issue is causing significant negative
business impact, please contact
Microsoft Product Support Services. I
regret that we could not provide a
better resolution. Rest assured that
we seriously considered this issue – a
Won’t Fix decision is never easy to
make.

This basically says the you should use DataContractSerializer instead of XmlSerializer or change your object structure.