在Visual Studio项目属性中，有一个选项显示“生成序列化程序集”。尝试为生成[包含MyType的程序集]的项目打开该选项。

另一方面，对编译错误进行故障排除是非常复杂的。这些问题在FileNotFoundException异常中显示，并显示如下信息:

File or assembly name abcdef.dll, or one of its dependencies, was not found. File name: "abcdef.dll"
   at System.Reflection.Assembly.nLoad( ... )
   at System.Reflection.Assembly.InternalLoad( ... )
   at System.Reflection.Assembly.Load(...)
   at System.CodeDom.Compiler.CompilerResults.get_CompiledAssembly() 

You may wonder what a file not found exception has to do with instantiating a serializer object, but remember: the constructor writes C# files and tries to compile them. The call stack of this exception provides some good information to support that suspicion. The exception occurred while the XmlSerializer attempted to load an assembly generated by CodeDOM calling the System.Reflection.Assembly.Load method. The exception does not provide an explanation as to why the assembly that the XmlSerializer was supposed to create was not present. In general, the assembly is not present because the compilation failed, which may happen because, under rare circumstances, the serialization attributes produce code that the C# compiler fails to compile.

请注意 当XmlSerializer在不能访问临时目录的帐户或安全环境下运行时，也会发生此错误。

来源: http://msdn.microsoft.com/en-us/library/aa302290.aspx

只是作为参考。从D-B的回答和评论中，我得出了这个接近D-B的解决方案。它在我的所有情况下都工作得很好，并且是线程安全的。我不认为使用ConcurrentDictionary是可以的。

using System;
using System.Collections.Generic;
using System.Xml.Serialization;

namespace HQ.Util.General
{
    public class XmlSerializerHelper
    {
        private static readonly Dictionary<Type, XmlSerializer> _dictTypeToSerializer = new Dictionary<Type, XmlSerializer>();

        public static XmlSerializer GetSerializer(Type type)
        {
            lock (_dictTypeToSerializer)
            {
                XmlSerializer serializer;
                if (! _dictTypeToSerializer.TryGetValue(type, out serializer))
                {
                    var importer = new XmlReflectionImporter();
                    var mapping = importer.ImportTypeMapping(type, null, null);
                    serializer = new XmlSerializer(mapping);
                    return _dictTypeToSerializer[type] = serializer;
                }

                return serializer;
            }
        }
    }
}

用法:

        if (File.Exists(Path))
        {
            using (XmlTextReader reader = new XmlTextReader(Path))
            {
                // XmlSerializer x  = new XmlSerializer(typeof(T));
                var x = XmlSerializerHelper.GetSerializer(typeof(T));

                try
                {
                    options = (OptionsBase<T>)x.Deserialize(reader);
                }
                catch (Exception ex)
                {
                    Log.Instance.AddEntry(LogType.LogException, "Unable to open Options file: " + Path, ex);
                }
            }
        }

Like Martin Sherburn said, this is normal behavior. The constructor of the XmlSerializer first tries to find an assembly named [YourAssembly].XmlSerializers.dll which should contain the generated class for serialization of your type. Since such a DLL has not been generated yet (they are not by default), a FileNotFoundException is thrown. When that happenes, XmlSerializer's constructor catches that exception, and the DLL is generated automatically at runtime by the XmlSerializer's constructor (this is done by generating C# source files in the %temp% directory of your computer, then compiling them using the C# compiler). Additional constructions of an XmlSerializer for the same type will just use the already generated DLL.

更新:从。net 4.5开始，XmlSerializer不再执行代码生成，也不再为了在运行时创建序列化程序集而使用c#编译器执行编译，除非通过设置配置文件设置(useLegacySerializerGeneration)显式强制执行。此更改消除了对csc.exe的依赖，并提高了启动性能。来源:. net Framework 4.5 Readme，章节1.3.8.1。

异常由XmlSerializer的构造函数处理。你不需要自己做任何事情，你可以点击“继续”(F5)继续执行你的程序，一切都会好的。如果你被异常停止程序执行并弹出异常助手所困扰，你要么关闭“只是我的代码”，要么将FileNotFoundException设置为在抛出时中断执行，而不是在“User-unhandled”时。

打开“Just My Code”，请转到“Tools >> Options >> Debugging >> General >> enable Just My Code”。要关闭FileNotFound被抛出时的执行中断，请转到调试>>异常>>找到>>输入'FileNotFoundException' >>取消System.IO.FileNotFoundException中的' thrown '复选框。

有一个变通的办法。如果你使用

XmlSerializer lizer = XmlSerializer.FromTypes(new[] { typeof(MyType) })[0];

它应该避免这种异常。这对我很管用。

警告:不要多次使用，否则会出现内存泄漏

如果多次使用此方法为同一类型创建XmlSerializer实例，将会导致内存严重泄漏!

这是因为该方法绕过了内置缓存提供的XmlSerializer(type)和XmlSerializer(type, defaultNameSpace)构造函数(所有其他构造函数也绕过缓存)。

如果使用任何方法来创建XmlSerializer，而不是通过这两个构造函数，那么必须实现自己的缓存，否则会导致内存泄漏。

此异常也可以由名为BindingFailure的托管调试助手(MDA)捕获。

如果您的应用程序被设计为附带预构建序列化程序集，则此MDA非常有用。这样做是为了提高应用程序的性能。它允许我们确保预先构建的序列化程序集由构建过程正确构建，并由应用程序加载，而无需动态重新构建。

除了在这种情况下，它实际上没什么用，因为正如其他帖子所说，当绑定错误被Serializer构造函数捕获时，序列化程序集将在运行时重新构建。所以你可以把它关掉。