[英]In C# I can't get my XML to deserialize into an object
我已经仔细阅读了与此类似的各种问题,但无法获得有效的解决方案。
我正在使用Visual Studio 2015社区,正在构建WPF项目。
我从后端API获取xml,并且试图将其转换为C#对象,但无法正常工作。
这是XML
<response>
<computer_setting id="1" hospital_name="foo" computer_type="bar" environment="staging" label_printer_name="labels" document_printer_name="docs"/>
</response>
这个课
using System.Xml.Serialization;
namespace Casechek.Kiosk
{
[XmlRoot("response")]
public class ComputerSettingResponse
{
[XmlElement("computer_setting")]
internal ComputerSetting Settings { get; set; }
}
internal class ComputerSetting
{
[XmlAttribute("id")]
internal string Id { get; set; }
[XmlAttribute("hospital_name")]
internal string HospitalName { get; set; }
[XmlAttribute("computer_type")]
internal string ComputerType { get; set; }
[XmlAttribute("environment")]
internal string Environment { get; set; }
[XmlAttribute("label_printer_name")]
internal string LabelPrinterName { get; set; }
[XmlAttribute("document_printer_name")]
internal string DocumentPrinterName { get; set; }
}
}
这是我反序列化的尝试
// Get ComputerSettings
String _Url = this.ApiUrl
+ "/api1/hospitals/foo/settings.xml"
+ "?access_token=" + Authentication.AccessToken;
XmlSerializer _Serializer = new XmlSerializer(typeof(ComputerSettingResponse));
ComputerSettingResponse _ComputerSettingResponse = new ComputerSettingResponse();
using (XmlTextReader _XmlReader = new XmlTextReader(_Url))
{
_ComputerSettingResponse = (ComputerSettingResponse)_Serializer.Deserialize(_XmlReader);
Debug.WriteLine(_ComputerSettingResponse.Settings.Environment);
}
但这会在到达Debug.WriteLine()时引发NullReference异常。
{“你调用的对象是空的。”}
我检查了网址是否正确返回了xml,因此它必须是构造不良的类,否则我无法正确进行反序列化。
Visual Studio有一些不错的工具可以从XML或JSON生成可序列化的类-只需将XML的示例复制到剪贴板,打开一个空的类文件,然后在Visual Studio中使用以下菜单路径将其粘贴为类: 编辑->选择性粘贴->将XML粘贴为类 ...或者,如果是JSON,则“粘贴JSON作为类”。
XDocument出现后(与Linq匹配),我停止了所有Xml Attribute voodoo。 此“映射”代码简单明了。
public class ComputerSettingResponse
{
internal ComputerSetting Settings { get; set; }
}
internal class ComputerSetting
{
internal string Id { get; set; }
internal string HospitalName { get; set; }
internal string ComputerType { get; set; }
internal string Environment { get; set; }
internal string LabelPrinterName { get; set; }
internal string DocumentPrinterName { get; set; }
}
string xmlString = @"<response>
<computer_setting id=""1"" hospital_name=""foo"" computer_type=""bar"" environment=""staging"" label_printer_name=""labels"" document_printer_name=""docs""/>
</response> ";
XDocument xDoc = XDocument.Parse(xmlString);
//XNamespace ns = XNamespace.Get("http://schemas.microsoft.com/developer/msbuild/2003");
string ns = string.Empty;
List<ComputerSettingResponse> collection = new List<ComputerSettingResponse>
(
from list in xDoc.Descendants(ns + "response")
from item1 in list.Elements(ns + "computer_setting")
where item1 != null
select new ComputerSettingResponse
{
//note that the cast is simpler to write than the null check in your code
//http://msdn.microsoft.com/en-us/library/bb387049.aspx
Settings = new ComputerSetting
(
)
{
Id = (string)item1.Attribute("id") ?? string.Empty,
HospitalName = (string)item1.Attribute("hospital_name") ?? string.Empty,
ComputerType = (string)item1.Attribute("computer_type") ?? string.Empty,
Environment = (string)item1.Attribute("environment") ?? string.Empty,
LabelPrinterName = (string)item1.Attribute("label_printer_name") ?? string.Empty,
DocumentPrinterName = (string)item1.Attribute("document_printer_name") ?? string.Empty
}
}
);
/* if you know there is only one */
ComputerSettingResponse returnItem = collection.FirstOrDefault();
在上面的代码中,您似乎将“ _Url”视为XML,但这只是后端API的URL,不是吗?
我尝试用示例XML替换它,并仅通过将类的可见性更改为public使其工作
所以这对我有用:
String xml = File.ReadAllText("XMLFile1.xml");
XmlSerializer _Serializer = new XmlSerializer(typeof(ComputerSettingResponse));
ComputerSettingResponse _ComputerSettingResponse = new ComputerSettingResponse();
using (StringReader reader = new StringReader(xml))
{
_ComputerSettingResponse = (ComputerSettingResponse)_Serializer.Deserialize(reader);
Debug.WriteLine(_ComputerSettingResponse.Settings.Environment);
}
使用这样的类:
using System.Xml.Serialization;
namespace Casechek.Kiosk
{
[XmlRoot("response")]
public class ComputerSettingResponse
{
[XmlElement("computer_setting")]
public ComputerSetting Settings { get; set; }
}
public class ComputerSetting
{
[XmlAttribute("id")]
public string Id { get; set; }
[XmlAttribute("hospital_name")]
public string HospitalName { get; set; }
[XmlAttribute("computer_type")]
public string ComputerType { get; set; }
[XmlAttribute("environment")]
public string Environment { get; set; }
[XmlAttribute("label_printer_name")]
public string LabelPrinterName { get; set; }
[XmlAttribute("document_printer_name")]
public string DocumentPrinterName { get; set; }
}
}
我调查了为什么它不能与内部声明一起使用,并找到了这样的答案,它帮助我了解了有关XmlSerializer内部的一些信息: https : //stackoverflow.com/a/6156822/3093396
希望这可以帮助。
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