Question

我的Xml看起来如下：

    <?xml version="1.0" encoding="UTF-8"?>
<SearchSuggestion xmlns="http://opensearch.org/searchsuggest2" version="2.0">
   <Query xml:space="preserve">middle ages</Query>
   <Section>
      <Item>
         <Text xml:space="preserve">Middle Ages</Text>
         <Url xml:space="preserve">https://en.wikipedia.org/wiki/Middle_Ages</Url>
         <Description xml:space="preserve">In the history of Europe, the Middle Ages or medieval period lasted from the 5th to the 15th century. It began with the fall of the Western Roman Empire and merged into the Renaissance and the Age of Discovery.</Description>
         <Image source="https://upload.wikimedia.org/wikipedia/commons/thumb/0/0a/JuengeresMathildenkreuz.jpg/35px-JuengeresMathildenkreuz.jpg" width="35" height="50" />
      </Item>
      <Item>
         <Text xml:space="preserve">Middle Ages in film</Text>
         <Url xml:space="preserve">https://en.wikipedia.org/wiki/Middle_Ages_in_film</Url>
         <Description xml:space="preserve">Medieval films imagine and portray the Middle Ages through the visual, audio and thematic forms of cinema.</Description>
         <Image source="https://upload.wikimedia.org/wikipedia/commons/thumb/3/39/Fairbanks_Robin_Hood_standing_by_wall_w_sword.jpg/40px-Fairbanks_Robin_Hood_standing_by_wall_w_sword.jpg" width="40" height="50" />
      </Item>
      <Item>
         <Text xml:space="preserve">Talk:Middle Ages/GA1</Text>
         <Url xml:space="preserve">https://en.wikipedia.org/wiki/Talk:Middle_Ages/GA1</Url>
      </Item>
      <Item>
         <Text xml:space="preserve">Talk:Middle Ages/Archive 4</Text>
         <Url xml:space="preserve">https://en.wikipedia.org/wiki/Talk:Middle_Ages/Archive_4</Url>
      </Item>
   </Section>
</SearchSuggestion>

我的对象如下所示：

[XmlRoot("SearchSuggestion", Namespace = "http://opensearch.org/searchsuggest2")]
    public class SearchItem
    {
        [XmlElement("Query")]
        public string query { get; set; }
        [XmlElement("Section")]
        public Section section { get; set; }

    }
    public class Section
    {
        [XmlElement("Item")]
        public Item[] items { get; set; }
    }
    public class Item
    {
        [XmlElement("Text")]
        public string Text { get; set; }
        [XmlElement("Url")]
        public string Url { get; set; }
        [XmlElement("Description")]
        public string Description { get; set; }
        [XmlElement("Image")]
        public Image Image { get; set; }
    }
    public class Image
    {
        [XmlAttribute("source")]
        public string source { get; set; }
    }

我的控制器如下所示：

        string wikiResponse; //raw response from REST endpoint
        SearchItem wikiXmlResponse = null; //Deserialized response


        wikiResponse = await httpClient.GetStringAsync(queryUri);
        var buffer = System.Text.Encoding.UTF8.GetBytes(wikiResponse);
        using (var stream = new MemoryStream(buffer)) {

        var serializer = new XmlSerializer(typeof(SearchItem));
        wikiXmlResponse = (SearchItem)serializer.Deserialize(stream);
       }
        Items [] infoResult = wikiXmlResponse.section.items;
        for (int i = 0; i < infoResultCount; i++)
            {
               Title = infoResult[i].Text;
               Explaination = infoResult[i].Description;
               Image_Url = infoResult[i].Image.source; 
               Article_Url = infoResult[i].Url; 
            }

我从维基百科Api获得的Xml响应，并且有时响应了一些元素，例如说明和图像丢失。避免异常的最佳方法是什么？

Answer 1

缺少元素导致没有例外（见this fiddle）。

此案例中的例外将是空引用例外，因为您试图从source null属性中读取Image。你需要处理这个问题：

Image_Url = infoResult[i].Image?.source;

如何在将Xml反序列化为C＃对象时因为某些缺少的Xml元素（例如描述和图像）而避免异常

1 个答案: