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如何从这种XML创建对象图?

.net-3.5 xml c#

code4life · 技术社区 · 14 年前

我的soap服务器向我发送的XML看起来像这样:

<?xml version='1.0' encoding='utf-8'?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
  <SOAP-ENV:Header xmlns:xxxxxx="...">
    <...bunch of soap header stuff.../>
  </SOAP-ENV:Header>
  <SOAP-ENV:Body>
    <queryResponse xmlns="...">
      <resultSet seqNo="0">
        <Types>
          <name>varchar</name>
          <value>varchar</value>
        </Types>
        <row>
          <name>field1</name>
          <value>0</value>
        </row>
        <row>
          <name>field2</name>
          <value>some string value</value>
        </row>
        <row>
          <name>field3</name>
          <value>false</value>
        </row>
        <... repeats for many more rows... />
      </resultSet>
    </queryResponse>
  </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

我怎么能拿 <row> 节点并填充以下类:

public class SessionProperties
{
  public int IntField {get;set;}
  public string StringField {get;set;}
  public bool BooleanField {get;set;}

  // more fields...
}

我想避免手动填充 SessionProperties 实例,例如。,

var myProps = new SessionProperties();
myProps.IntField = XElement("...").Value;  // I don't want to do this!

另外,我不想编写一个IXmlSerializable实现,我认为这只会使代码更加复杂。但如果我错了就告诉我。

最后,soap服务器可能会在将来向我发送额外的行节点,我只想更新 会话属性 如果可能的话,上课。是否有一些通用方法(可能使用自定义属性等)可以实现这一点?

提前谢谢!

3 回复 | 直到 14 年前

Robert Rossney 14 年前

我认为这应该不言而喻:

    class Program
    {
        // map names in the XML to the names of SessionInfo properties;
        // you'll need to update this when you add a new property to
        // the SessionInfo class:
        private static Dictionary<string, string> PropertyMap = 
            new Dictionary<string, string>
        {
            {"field1", "StringProperty1"},
            {"field2", "IntProperty1"},
            {"field3", "BoolProperty1"},
        };

        // map CLR types to XmlConvert methods; you'll need one entry in
        // this map for every CLR type SessionInfo uses
        private static Dictionary<Type, Func<string, object>> TypeConverterMap = 
            new Dictionary<Type, Func<string, object>>
        {
            { typeof(bool), x => XmlConvert.ToBoolean(x)},
            { typeof(int), x => XmlConvert.ToInt32(x)},
            { typeof(string), x => x},
        };

        static void Main(string[] args)
        {
            // map SessionInfo's property names to their PropertyInfo objects
            Dictionary<string, PropertyInfo> properties = AppDomain.CurrentDomain.GetAssemblies()
                .SelectMany(x => x.GetExportedTypes())
                .Where(x => x.Name == "SessionInfo")
                .SelectMany(x => x.GetMembers())
                .Where(x => x.MemberType == MemberTypes.Property)
                .Cast<PropertyInfo>()
                .ToDictionary(x => x.Name);

            string xml =
                @"<example>
<row>
    <name>field1</name>
    <value>stringProperty</value>
</row>
<row>
    <name>field2</name>
    <value>123</value>
</row>
<row>
    <name>field3</name>
    <value>true</value>
</row>
</example>";
            XmlDocument d = new XmlDocument();
            d.LoadXml(xml);

            SessionInfo s = new SessionInfo();

            // populate the object's properties from the values in the XML
            foreach (XmlElement elm in d.SelectNodes("//row"))
            {
                string name = elm.SelectSingleNode("name").InnerText;
                string value = elm.SelectSingleNode("value").InnerText;
                // look up the property for the name in the XML and get its
                // PropertyInfo object
                PropertyInfo pi = properties[PropertyMap[name]];
                // set the property to the value in the XML, using the the converter for 
                // the property's type
                pi.SetValue(s, TypeConverterMap[pi.PropertyType](value), null);
            }

            // and the results:
            Console.WriteLine(s.StringProperty1);
            Console.WriteLine(s.IntProperty1);
            Console.WriteLine(s.BoolProperty1);
            Console.ReadKey();
        }

user1228 user1228 14 年前

嗯,那个XML有点不好。

如果是我,我会为您的soap结果创建一个包装器类型,它实现 ICustomTypeDescriptor

自定义类型描述符执行与普通反射相同的操作,但允许类型创建者为调用方处理反射过程。默认实现 TypeDescriptor

这样做的真正好处是 .

<TextBox Text="{Binding Session.UserName}" />

即使是你真正喜欢的类型 没有用户名属性

我不是说这会很容易,但一旦你得到了核心概念,这绝对不是那么难。

code4life 14 年前

这个解决方案演示了自定义属性的使用,正如Robert所建议的那样。

// match the properties to the xml dynamically using this attribute...
[AttributeUsage(AttributeTargets.Property)]
public class DBSPropAttribute : Attribute
{
    public string MappingField { get; set; }
    public DBSPropAttribute(string fieldName)
    {
        MappingField = fieldName;
    }
}

然后将自定义属性应用于SessionProperties类,如下所示:

[DBSProp("archiveDays")]
public int ArchiveDays { get; set; }

在SessionProperties类中,我还将定义这个转换器字典,这是Robert的一个非常优雅的想法:

// map CLR types to convert methods; you'll need one entry in
// this map for every CLR type
private static readonly Dictionary<Type, Func<string, object>> TypeConverterMap =
    new Dictionary<Type, Func<string, object>>
{
    { typeof(bool), x => Convert.ToBoolean(x)},
    { typeof(int), x => Convert.ToInt32(x)},
    { typeof(string), x => x},
    { typeof(double), x => Convert.ToDouble(x)}
};

public void SetPropertyValues(IEnumerable<XElement> elements)
{
    var propList = typeof(SessionProperties).GetProperties();

    foreach (var elm in elements)
    {
        var nm = elm.Element("name").Value;
        var val = elm.Element("value").Value;

        // MUST throw an exception if there are no matches...
        var pi = propList.First(c => c.GetCustomAttributes(true)
                   .OfType<DBSPropAttribute>()
                   .First()
                   .MappingField == nm);

        pi.SetValue(this, TypeConverterMap[pi.PropertyType](val), null);
    }
}

再次感谢罗伯特阐述了导致这个答案的关键概念。我认为这是一个很好的替代他同样有效的方法。