我正在尝试做一个 XML 解析器，它将使用 REST 服务从网站中提取数据，通信协议是 HTTP，我得到的数据是 XML 格式，在对不同地址的多次请求后，我得到了我需要的数据服务器。我需要将这些数据解析为 c# 对象，以便最近可以使用它们。服务器上的信息分为 5 个级别（我愿意只做其中的 4 个） 1-供应商列表 2-组列表 3-子组列表 4-产品列表 5-有关完整信息的列表产品 达到第 4 级后，我需要检查产品是否在我的数据库中，或者它是否有不同的详细信息，以便我可以添加或更新它。
通过对服务器的“GET”请求，我得到具有这种结构的 XML：
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<vendors>
<vendor>
<id>someID</id>
<name>someName</name>
</vendor>
<vendor>
<id>someId1</id>
<name>somename1</name>
</vendor>
</vendors>
组的 XML 结构是相同的：
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<groups vendor_id="43153185318">
<group>
<id>someID</id>
<name>someName</name>
</group>
<group>
<id>someId1</id>
<name>somename1</name>
</group>
XML 结构对于子组和产品是类比的，除了对于产品我有更多的元素，如目录编号、价格等。
我的课程如下：
public class VendorList
{
public List<Vendor> vendor_list { get; set; }
public VendorList()
{
vendor_list = new List<Vendor>();
}
}
public class Vendor
{
public string id { get; set; }
public string name { get; set; }
public List<Group> groups_list { get; set; }
public Vendor()
{
id = "N/A";
name = "N/A";
groups_list = new List<Group>();
}
}
public class Group
{
public string id { get; set; }
public string name { get; set; }
public List<SubGroup> subgroup_list { get; set; }
public Group()
{
id = "N/A";
name = "N/A";
subgroup_list = new List<SubGroup>();
}
}
public class SubGroup
{
public string id { get; set; }
public string name { get; set; }
public List<Product> product_list { get; set; }
public SubGroup()
{
id = "N/A";
name = "N/A";
product_list = new List<Product>();
}
}
public class Product
{
public string available { get; set; }
public string catalog_num { get; set; }
public string code { get; set; }
public string currency { get; set; }
public string description { get; set; }
public string haracteristics { get; set; }
public string product_id { get; set; }
public string model { get; set; }
public string name { get; set; }
public string price { get; set; }
public string price_dds { get; set; }
public string picture_url { get; set; }
public Product()
{
available = "N/A";
catalog_num = "N/A";
code = "N/A";
currency = "N/A";
description = "N/A";
haracteristics = "N/A";
product_id = "N/A";
model = "N/A";
name = "N/A";
price = "N/A";
price_dds = "N/A";
picture_url = "N/A";
}
}
和这样的 Parser 方法：
public static void FillVendor(string url)
{
string result = GetXMLstream(url);
var vendors = new VendorList();
XmlDocument doc = new XmlDocument();
doc.Load(new StringReader(result));
doc.Save(@"D:/proba/proba.xml");
XDocument d = XDocument.Load(@"D:/proba/proba.xml");
vendors.vendor_list = (from c in d.Descendants("vendor")
select new Vendor()
{
id = c.Element("id").Value,
name = c.Element("name").Value
}).ToList<Vendor>();
foreach (Vendor v in vendors.vendor_list)
{
FillGroups(v.id);
}
}
public static void FillGroups(string vendorID)
{
string url = "main address" + vendorID;
string result = GetXMLstream(url);
var group = new Vendor();
XmlDocument doc = new XmlDocument();
doc.Load(new StringReader(result));
doc.Save(@"D:/proba/proba1.xml");
XDocument d = XDocument.Load(@"D:/proba/proba1.xml");
group.groups_list = (from g in d.Descendants("group")
select new Group()
{
id = g.Element("id").Value,
name = g.Element("name").Value
}).ToList<Group>();
foreach (Group g in group.groups_list)
{
FillSubGroup(vendorID, g.id);
}
}
public static void FillSubGroup(string vendorID, string groupID)
{
string url = "main address" + vendorID+"/"+groupID;
string result = GetXMLstream(url);
var subgroup = new Group();
XmlDocument doc = new XmlDocument();
doc.Load(new StringReader(result));
doc.Save(@"D:/proba/proba2.xml");
XDocument d = XDocument.Load(@"D:/proba/proba2.xml");
subgroup.subgroup_list = (from g in d.Descendants("subgroup")
select new SubGroup()
{
id = g.Element("id").Value,
name = g.Element("name").Value
}).ToList<SubGroup>();
foreach (SubGroup sb in subgroup.subgroup_list)
{
FillProduct(vendorID, groupID, sb.id);
}
}
public static void FillProduct(string vendorID,string groupID,string subgroupID)
{
string url = "main address" + vendorID + "/" + groupID+"/"+subgroupID;
string result = GetXMLstream(url);
var product = new SubGroup();
XmlDocument doc = new XmlDocument();
doc.Load(new StringReader(result));
doc.Save(@"D:/proba/proba2.xml");
XDocument d = XDocument.Load(@"D:/proba/proba2.xml");
product.product_list = (from g in d.Descendants("subgroup")
select new Product()
{
available = g.Element("available").Value,
catalog_num = g.Element("catalog_num").Value,
code = g.Element("code").Value,
currency = g.Element("currency").Value,
description = g.Element("description").Value,
haracteristics = g.Element("haracteristics").Value,
product_id = g.Element("id").Value,
model = g.Element("model").Value,
name = g.Element("name").Value,
price = g.Element("price").Value,
price_dds = g.Element("price_dds").Value,
picture_url = g.Element("small_picture").Value,
}).ToList<Product>();
}
但是在完成解析后，我尝试检查我的列表是否填充了对象，但是我收到一个错误，说它们是空的“NullReferenceException”所以我的问题是我是否正确地制作了类并且我的解析方法是否正确（你可以建议如何解析xml而不在我的计算机上创建文件），如果我没有，我的错误在哪里，我应该如何让它正常工作？提前致谢！