解析Web服务响应返回的XML

Question

我在SO上读到了很多关于这个主题的问题，但似乎没有人能够解决我的问题。基本上，我正在调用一个Web服务来返回有关车辆识别号（VIN）的信息。它返回一个看起来像这样的xml流：

<VINquery Version="1.0.0" Date="5/25/2003">
  <VIN Number="1HGES15501Lxxxxxx" Status="SUCCESS">
    <Vehicle VINquery_Vehicle_ID="23261" Model_Year="2001" Make="Honda" Model="Civic" Trim_Level="LX Sedan">
      <Item Key="VINquery Vehicle ID" Value="23261" Unit=""/>
      <Item Key="Model Year" Value="2001" Unit=""/>
      <Item Key="Make" Value="Honda" Unit=""/>
      <Item Key="Model" Value="Civic" Unit=""/>
      <Item Key="Trim Level" Value="LX Sedan" Unit=""/>
      <Item Key="Manufactured in" Value="UNITED STATES" Unit=""/>
      <Item Key="Production Seq. Number" Value="xxxxxx" Unit=""/>
      <Item Key="Body Style" Value="SEDAN 4-DR" Unit=""/>
      <Item Key="Engine Type" Value="1.7L L4 SOHC 16V" Unit=""/>
      <Item Key="Transmission-short" Value="5M OD" Unit=""/>
      <Item Key="Transmission-long" Value="5-Speed Manual Overdrive" Unit=""/>
      <Item Key="Driveline" Value="FWD" Unit=""/>
      <Item Key="Tank" Value="13.20" Unit="gallon"/>
      <Item Key="Fuel Economy-city" Value="30 - 32" Unit="miles/gallon"/>
      <Item Key="Fuel Economy-highway" Value="38 - 39" Unit="miles/gallon"/>
      <Item Key="Anti-Brake System" Value="Non-ABS" Unit=""/>
      <Item Key="Steering Type" Value="R&P" Unit=""/>
      <Item Key="Standard Seating" Value="5" Unit=""/>
      <Item Key="Optional Seating" Value="No data" Unit=""/>
      <Item Key="Length" Value="174.60" Unit="in."/>
      <Item Key="Width" Value="67.50" Unit="in."/>
      <Item Key="Height" Value="56.70" Unit="in."/>
    </Vehicle>
  </VIN>
</VINquery>

我希望将数据解析为每个键/值对。这是我用来获取xml数据的代码:

private string baseURL = "http://ws.vinquery.com/restxml.aspx?accessCode=xxxxxx&vin=xxxxxxxxx";
private string reportType = "&reportType=2";

public XmlDocument ExplodeVIN(string strVIN)
{
   DataTable dt = new DataTable();

   string url = baseURL + strVIN + reportType;

   HttpWebRequest req = WebRequest.Create(url) as HttpWebRequest;

   XmlDocument xmlDoc = new XmlDocument();
   using (HttpWebResponse resp = req.GetResponse() as HttpWebResponse)
   {
     xmlDoc.Load(resp.GetResponseStream());
   }
   return xmlDoc;
}

在我获取了xmlDoc之后，我不确定接下来该做什么。

感谢您的帮助。

- Ryan

Answer 1

您可以使用 Linq to Xml 将 xml 解析为 Dictionary<string, string> ：

var xdoc = XDocument.Parse(xml);
var items = xdoc.Descendants("Item")
                .ToDictionary(i => (string)i.Attribute("Key"),
                              i => (string)i.Attribute("Value"));

使用方法：

string driveline = items["Driveline"];

或者

foreach(var kvp in items)
    // use key value pair

- Sergey Berezovskiy

---

我不理解你的这行代码：var xdoc = XDocument.Parse(xml)。Parse方法需要一个字符串，那么这个xml字符串从哪里来的呢？ - Ryan

@Ryan 那应该是服务响应字符串。如果你有响应流，请使用 XDocument.Load(stream)。 - Sergey Berezovskiy

这似乎接近工作状态...var items = xdoc.Descendants("Item").ToDictionary(i => (string)i.Element("Key"), i => (string)i.Element("Value")); 导致参数空异常，我不确定原因是什么。 - Ryan

@Ryan 抱歉，是我犯了错。Key和Value是属性而不是元素。我已经修好了代码。此外，你在Steering Type键的XML中未转义“＆”符号。应该将“＆”转义为“＆amp;”。 - Sergey Berezovskiy

Answer 2

XmlDocument xmldoc = new XmlDocument();
XmlNodeList xmlnodelstTrack = xmldoc.GetElementsByTagName("Item");
foreach (XmlNode NodeObj in xmlnodelstTrack)
{
  //Do stuff with NodeObj.OuterXml

}

- Rahul

---

我也喜欢这个解决方案。在我的 XML 示例中，我应该传递“Vehicle”节点以获取项目节点的键/值吗？还是我应该传递“Item”以在循环中获取键/值？ - Ryan

Answer 3

我通常使用另一种方法来处理xml。

步骤1：将你的xml字符串复制并粘贴为类。

当你粘贴时，这段代码将自动生成：

        /// <remarks/>
        [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
        [System.Xml.Serialization.XmlRootAttribute(Namespace = "", IsNullable = false)]
        public partial class VINquery
        {

            private VINqueryVIN vINField;

            private string versionField;

            private string dateField;

            /// <remarks/>
            public VINqueryVIN VIN
            {
                get
                {
                    return this.vINField;
                }
                set
                {
                    this.vINField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Version
            {
                get
                {
                    return this.versionField;
                }
                set
                {
                    this.versionField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Date
            {
                get
                {
                    return this.dateField;
                }
                set
                {
                    this.dateField = value;
                }
            }
        }

        /// <remarks/>
        [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
        public partial class VINqueryVIN
        {

            private VINqueryVINVehicle vehicleField;

            private string numberField;

            private string statusField;

            /// <remarks/>
            public VINqueryVINVehicle Vehicle
            {
                get
                {
                    return this.vehicleField;
                }
                set
                {
                    this.vehicleField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Number
            {
                get
                {
                    return this.numberField;
                }
                set
                {
                    this.numberField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Status
            {
                get
                {
                    return this.statusField;
                }
                set
                {
                    this.statusField = value;
                }
            }
        }

        /// <remarks/>
        [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
        public partial class VINqueryVINVehicle
        {

            private VINqueryVINVehicleItem[] itemField;

            private ushort vINquery_Vehicle_IDField;

            private ushort model_YearField;

            private string makeField;

            private string modelField;

            private string trim_LevelField;

            /// <remarks/>
            [System.Xml.Serialization.XmlElementAttribute("Item")]
            public VINqueryVINVehicleItem[] Item
            {
                get
                {
                    return this.itemField;
                }
                set
                {
                    this.itemField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public ushort VINquery_Vehicle_ID
            {
                get
                {
                    return this.vINquery_Vehicle_IDField;
                }
                set
                {
                    this.vINquery_Vehicle_IDField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public ushort Model_Year
            {
                get
                {
                    return this.model_YearField;
                }
                set
                {
                    this.model_YearField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Make
            {
                get
                {
                    return this.makeField;
                }
                set
                {
                    this.makeField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Model
            {
                get
                {
                    return this.modelField;
                }
                set
                {
                    this.modelField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Trim_Level
            {
                get
                {
                    return this.trim_LevelField;
                }
                set
                {
                    this.trim_LevelField = value;
                }
            }
        }

        /// <remarks/>
        [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
        public partial class VINqueryVINVehicleItem
        {

            private string keyField;

            private string valueField;

            private string unitField;

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Key
            {
                get
                {
                    return this.keyField;
                }
                set
                {
                    this.keyField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Value
            {
                get
                {
                    return this.valueField;
                }
                set
                {
                    this.valueField = value;
                }
            }

            /// <remarks/>
            [System.Xml.Serialization.XmlAttributeAttribute()]
            public string Unit
            {
                get
                {
                    return this.unitField;
                }
                set
                {
                    this.unitField = value;
                }
            }
        }

步骤二：将您的XML字符串反序列化为此生成的类。

public T DeserializeXML<T>(string xmlContent)
{
    XmlSerializer serializer = new XmlSerializer(typeof(T));
    MemoryStream memStream = new MemoryStream(Encoding.UTF8.GetBytes(xmlContent));
    return (T)serializer.Deserialize(memStream);
}

....
string resultXml = resp.GetResponseStream();
VINquery resultObject = DeserializeXML<VINquery>(resultObject); 

现在，您可以轻松地操作和过滤您的结果。

附注：您必须删除XML字符串中的特殊字符（&），因为当您尝试将其粘贴为类时会引起问题。

- GorkemHalulu

---

当响应非常长，即10Mb时，您有什么使用此方法的提示吗？ - n1k31t4