我有一个大型 XML 文档,我想使用 XmlSerializer
类插入新元素,这些元素的内容来自使用 xsd.exe 生成的 .NET 类实例。
这是问题 How to deserialize a node in a large document using XmlSerializer 的后续问题,并使用该问题中描述的相同 xsd 和生成的类。
假设在我的示例 XML 中,我想用我的福特汽车换一辆宝马汽车。我尝试了以下代码:
static string XmlContent = @"
<RootNode xmlns=""http://MyNamespace"">
<Cars>
<Car make=""Volkswagen"" />
<Car make=""Ford"" />
<Car make=""Opel"" />
</Cars>
</RootNode>";
private static void TestWriteMcve()
{
var doc = new XmlDocument();
doc.LoadXml(XmlContent);
var nsMgr = new XmlNamespaceManager(doc.NameTable);
nsMgr.AddNamespace("myns", "http://MyNamespace");
var node = doc.DocumentElement.SelectSingleNode("myns:Cars/myns:Car[@make='Ford']", nsMgr);
var parent = node.ParentNode;
var carSerializer = new XmlSerializer(typeof(Car));
using (var writer = node.CreateNavigator().InsertAfter())
{
// WriteWhitespace needed to avoid error "WriteStartDocument cannot
// be called on writers created with ConformanceLevel.Fragment."
writer.WriteWhitespace("");
var newCar = new Car { make = "BMW" };
carSerializer.Serialize(writer, newCar);
}
parent.RemoveChild(node);
Console.WriteLine(parent.OuterXml);
}
我得到的结果接近我想要的:
<Cars xmlns="http://MyNamespace">
<Car make="Volkswagen" />
<Car xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" make="BMW" xmlns="" />
<Car make="Opel" />
</Cars>
除了添加的元素上所有不需要的 xmlns:...
属性。它们从何而来?我该如何摆脱它们?
最佳答案
如中所述Omitting all xsi and xsd namespaces when serializing an object in .NET? ,XmlSerializer
将在序列化时始终有助于添加 xsi
和 xsd
命名空间。如果您不希望这样,则需要调用 Serialize
的重载,其中可以指定所需的初始 namespace ,例如XmlSerializer.Serialize(XmlWriter, Object, XmlSerializerNamespaces)
.以下扩展方法可以解决问题:
public static class XmlNodeExtensions
{
public static XmlNode ReplaceWithSerializationOf<T>(this XmlNode node, T replacement)
{
if (node == null)
throw new ArgumentNullException();
var parent = node.ParentNode;
var serializer = new XmlSerializer(replacement == null ? typeof(T) : replacement.GetType());
using (var writer = node.CreateNavigator().InsertAfter())
{
// WriteWhitespace needed to avoid error "WriteStartDocument cannot
// be called on writers created with ConformanceLevel.Fragment."
writer.WriteWhitespace("");
// Set up an appropriate initial namespace.
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add(node.GetNamespaceOfPrefix(node.NamespaceURI), node.NamespaceURI);
// Serialize
serializer.Serialize(writer, replacement, ns);
}
var nextNode = node.NextSibling;
parent.RemoveChild(node);
return nextNode;
}
}
然后按如下方式使用:
var newCar = new Car { make = "BMW" };
var node = doc.DocumentElement.SelectSingleNode("myns:Cars/myns:Car[@make='Ford']", nsMgr);
node = node.ReplaceWithSerializationOf(newCar);
var parent = node.ParentNode;
之后,为 doc
生成的 XML 将是:
<RootNode xmlns="http://MyNamespace">
<Cars>
<Car make="Volkswagen" />
<Car make="BMW" />
<Car make="Opel" />
</Cars>
</RootNode>
sample 加工 .Net fiddle .
关于c# - 如何使用 XmlSerializer 在大型文档中插入节点,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/48659674/