当您创建XmlSerializer的实例时,使用仅具有一个Type参数的构造函数,它会检查缓存并查找预生成的程序集.
但是当您使用带有XmlAttributeOverrides的构造函数时,XmlSerializer不会检查任何缓存并立即生成临时程序集.

最有可能的原因是,由于序列化逻辑中的相当激进的变化,您可以使用XmlAttributeOverrides参数来实现,这在sgen之类的工具中无法在编译时“预见”.

如果你需要预编译的东西,你[叹气]必须避免使用XmlAttributeOverrides.如果无法做到这一点,请尝试提前创建所需的XmlSerializer实例,可能在后台线程中.

只是为了您的兴趣,这里是默认构造函数的代码(检查缓存并尝试查找预先生成的程序集)：

public XmlSerializer(Type type,string defaultNamespace)
{
    this.events = new XmlDeserializationEvents();
    if (type == null)
    {
        throw new ArgumentNullException("type");
    }
    this.mapping = GetKnownMapping(type,defaultNamespace);
    if (this.mapping != null)
    {
        this.primitiveType = type;
    }
    else
    {
        this.tempAssembly = cache[defaultNamespace,type];
        if (this.tempAssembly == null)
        {
            lock (cache)
            {
                this.tempAssembly = cache[defaultNamespace,type];
                if (this.tempAssembly == null)
                {
                    XmlSerializerImplementation implementation;
                    Assembly assembly = TempAssembly.LoadGeneratedAssembly(type,defaultNamespace,out implementation);
                    if (assembly == null)
                    {
                        this.mapping = new XmlReflectionImporter(defaultNamespace).ImportTypeMapping(type,null,defaultNamespace);
                        this.tempAssembly = GenerateTempAssembly(this.mapping,type,defaultNamespace);
                    }
                    else
                    {
                        this.mapping = XmlReflectionImporter.GetTopLevelMapping(type,defaultNamespace);
                        this.tempAssembly = new TempAssembly(new XmlMapping[] { this.mapping },assembly,implementation);
                    }
                }
                cache.Add(defaultNamespace,this.tempAssembly);
            }
        }
        if (this.mapping == null)
        {
            this.mapping = XmlReflectionImporter.GetTopLevelMapping(type,defaultNamespace);
        }
    }
}

这里是与XmlAttributeOverrides一起使用的构造函数(总是生成序列化程序集)：

public XmlSerializer(Type type,XmlAttributeOverrides overrides,Type[] extraTypes,XmlRootAttribute root,string defaultNamespace,string location,Evidence evidence)
{
    this.events = new XmlDeserializationEvents();
    if (type == null)
    {
        throw new ArgumentNullException("type");
    }
    XmlReflectionImporter importer = new XmlReflectionImporter(overrides,defaultNamespace);
    for (int i = 0; i < extraTypes.Length; i++)
    {
        importer.IncludeType(extraTypes[i]);
    }
    this.mapping = importer.ImportTypeMapping(type,root,defaultNamespace);
    if (location != null)
    {
        this.DemandForUserLocation();
    }
    this.tempAssembly = GenerateTempAssembly(this.mapping,location,evidence);
}