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C#泛型序列化实用程序类

constraints xml-serialization generics c#

Sarah Vessels · 技术社区 · 14 年前

我有一个用于序列化和反序列化XML对象的现有类。它是一个泛型类,只有一个类型参数 T 唯一的限制是 where T : IXmlSerializable . 但是,我仍然希望能够在未实现的类上使用这个类 IXmlSerializable 但是你有 [Serializable]

从我的泛型类:

public static class XmlSerializationUtils<T> where T : IXmlSerializable
{
    public static T DeserializeXml(XmlDocument xml) { ... }
    public static XmlDocument SerializeToXml(T toSerialize) { ... }
}

我发现 this discussion where T : Serializable . 试着去做 where T : SerializableAttribute 使Visual Studio说“不能将密封类'System.SerializableAttribute'用作类型参数约束”。

基于 Stephen's answer ,我删除了 XmlSerializationUtils<T> 并添加了这个静态构造函数:

static XmlSerializationUtils()
{
    Type type = typeof(T);
    bool hasAttribute = null != Attribute.GetCustomAttribute(type,
        typeof(SerializableAttribute));
    bool implementsInterface =
        null != type.GetInterface(typeof(IXmlSerializable).FullName);
    if (!hasAttribute && !implementsInterface)
    {
        throw new ArgumentException(
            "Cannot use XmlSerializationUtils on class " + type.Name +
            " because it does not have the Serializable attribute " +
            " and it does not implement IXmlSerializable"
        );
    }
}

3 回复 | 直到 8 年前

Steven Sudit 14 年前

womp 14 年前

IsSerializable 对象类型的属性。

myObj.GetType().IsSerializable

如前所述,这不可能作为泛型约束添加,但很可能在构造函数中进行检查。

Charles Bretana 14 年前

当类型没有正确序列化或反序列化时,我只需要消除类型约束并捕获SerializationException。。。实际上,这允许泛型序列化和反序列化方法接受格式化程序

public enum Formatter { Binary, Xml }

public class Serialization
{
    public enum Formatter { Binary, Xml }

    #region Serialization methods
    public static void Serialize2File<T>(T obj, string pathSpec, 
        Formatter formatter)
    {
        try
        {
            switch (formatter)
            {
                case (Formatter.Binary):
                    using (var fs = new FileStream(pathSpec, FileMode.Create,
                                        FileAccess.Write, FileShare.Write))
                        (new BinaryFormatter()).Serialize(fs, obj);
                    break;

                case (Formatter.Xml):
                    var serializer = new XmlSerializer(typeof(T));
                    TextWriter textWriter = new StreamWriter(pathSpec);
                    serializer.Serialize(textWriter, obj);
                    textWriter.Close();
                    break;

                default:
                    throw new MyCustomException("Invalid Formatter option");
            }
        }
        catch (SerializationException sX)
        {
            var errMsg = String.Format(
                "Unable to serialize {0} into file {1}",
                obj, pathSpec);
            throw new MyCustomException(errMsg, sX);
        }
    }
    public static T DeSerializeFromFile<T>(string pathSpec, 
        Formatter formatter) where T : class
    {
        try
        {
            switch (formatter)
            {
                case (Formatter.Binary):
                    using (var strm = new FileStream(pathSpec,
                                        FileMode.Open, FileAccess.Read))
                    {
                        IFormatter fmt = new BinaryFormatter();
                        var o = fmt.Deserialize(strm);
                        if (!(o is T))
                            throw new ArgumentException("Bad Data File");
                        return o as T;
                    }

                case (Formatter.Xml):
                    var serializer = new XmlSerializer(typeof(T));
                    TextReader rdr = new StreamReader(pathSpec);
                    return (T)serializer.Deserialize(rdr);

                default:
                    throw new MyCustomException("Invalid Formatter option");
            }
        }
        catch (SerializationException sX)
        {
            var errMsg = String.Format(
                "Unable to deserialize {0} from file {1}",
                typeof(T), pathSpec);
            throw new MyCustomException(errMsg, sX);
        }
    }
    #endregion Serialization methods
}