我一直在使用的一个应用程序在尝试序列化类型时失败了。

像这样的陈述

XmlSerializer lizer = new XmlSerializer(typeof(MyType));

生产:

System.IO.FileNotFoundException occurred
  Message="Could not load file or assembly '[Containing Assembly of MyType].XmlSerializers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified."
  Source="mscorlib"
  FileName="[Containing Assembly of MyType].XmlSerializers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
  FusionLog=""
  StackTrace:
       at System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection)
       at System.Reflection.Assembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection)

我没有为我的类定义任何特殊的序列化器。

我该如何解决这个问题?


当前回答

Martin Sheburn最初的回答是正确的。 来自edeboursetty, tomas-kubes)的代码示例,quadfinity应该解决在调试器中不引发过量异常的问题。

这里有一个简短的解决方案:

internal sealed static class XmlSerializerHelper
{
    private static readonly ConcurrentDictionary<Type, System.Xml.Serialization.XmlSerializer> s_xmlSerializers = new();

    public static System.Xml.Serialization.XmlSerializer Get<T>()
    {
        return s_xmlSerializers.GetOrAdd(typeof(T), _ => System.Xml.Serialization.XmlSerializer.FromTypes(new [] {typeof(T)})[0]);
    }
}

其他回答

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。

我遇到了这个问题,上面提到的任何解决方案都无法解决它。

后来我终于找到了解决办法。 序列化器似乎不仅需要类型,还需要嵌套类型。 改变:

XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));

:

XmlSerializer xmlSerializer = new XmlSerializer(typeof(T).GetNestedTypes());

为我修正了这个问题。 没有什么例外。

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);
                }
            }
        }

为了避免异常,你需要做两件事:

向序列化类添加属性(我希望您有访问权限) 使用sgen.exe生成序列化文件

将System.Xml.Serialization.XmlSerializerAssembly属性添加到类中。 将'MyAssembly'替换为MyClass所在程序集的名称。

[Serializable]
[XmlSerializerAssembly("MyAssembly.XmlSerializers")]
public class MyClass
{
…
}

使用sgen.exe实用程序生成序列化文件,并将其与类的程序集一起部署。

' sgen.exe MyAssembly.dll '将生成文件myassembly . xmlserializer .dll

这两个更改将导致.net直接查找程序集。 我检查了一下,它在。net框架3.5和Visual Studio 2008上工作

我的解决方案是直接使用反射来创建序列化器。这就绕过了导致异常的奇怪文件加载。我将其打包在一个helper函数中,该函数还负责缓存序列化器。

private static readonly Dictionary<Type,XmlSerializer> _xmlSerializerCache = new Dictionary<Type, XmlSerializer>();

public static XmlSerializer CreateDefaultXmlSerializer(Type type) 
{
    XmlSerializer serializer;
    if (_xmlSerializerCache.TryGetValue(type, out serializer))
    {
        return serializer;
    }
    else
    {
        var importer = new XmlReflectionImporter();
        var mapping = importer.ImportTypeMapping(type, null, null);
        serializer = new XmlSerializer(mapping);
        return _xmlSerializerCache[type] = serializer;
    }
}