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如何在不读取C的情况下检查xml中是否存在另一个节点#

xmlreader xml c#

2

Courtney Wright · 技术社区 · 9 年前

private Task<List<TAxEntity>> Deserialize(XmlReader reader)
    {
        var deserializer = new XmlSerializer(typeof(TAxEntity));
        var entities = new List<TAxEntity>();

        do
        {
            using (var stringReader = new StringReader(reader.ReadOuterXml()))
            {
                var entity = (TAxEntity)deserializer.Deserialize(stringReader);

                entities.Add(entity);
            }
        }
        while (reader.ReadToNextSibling(EntityElementName));

        return Task.FromResult(entities);
    }

1 回复 | 直到 9 年前

1

0

dbc 9 年前

XmlReader 已正确定位,您可以检查 reader.NodeType == XmlNodeType.Element 和 reader.Name == EntityElementName 。然后,如果读卡器已正确定位,请不要使用 ReadToNextSibling() .

而不是检查正确的 reader.Name LocalName 和 NamespaceURI reader.ReadToNextSibling(string localName,string namespaceURI) bug to be avoided
而不是 ReadOuterXml() 呼叫 reader.ReadSubtree() 并将返回的读取器直接传递给 deserializer.Deserialize() ReadSubtree() 允许 XmlSerializer 直接从传入的

综上所述,您可以引入以下低级扩展方法:

public static class XmlReaderExtensions
{
    public static IEnumerable<TElement> DeserializeSequence<TElement>(this XmlReader reader, string localEntityElementName, string namespaceURI)
    {
        if (reader == null)
            throw new ArgumentNullException();
        var deserializer = new XmlSerializer(typeof(TElement));
        while ((reader.NodeType == XmlNodeType.Element && reader.LocalName == localEntityElementName && reader.NamespaceURI == namespaceURI)
            || reader.ReadToNextSibling(localEntityElementName, namespaceURI))
        {
            // Using ReadSubtree instead of ReadOuterXml() avoids having do parse, reformat, then parse the formatted XML a second time
            // by reading directly from the current stream only once.
            TElement element;
            using (var subReader = reader.ReadSubtree())
            {
                element = (TElement)deserializer.Deserialize(subReader);
            }
            // Consume the EndElement also (or move past the current element if reader.IsEmptyElement).
            reader.Read();
            yield return element;
        }
    }
}

Deserialize() 方法如下:

    private Task<List<TAxEntity>> Deserialize(XmlReader reader)
    {
        var entities = reader.DeserializeSequence<TAxEntity>(EntityElementName, "" /* Pass the correct namespace here */).ToList();

        return Task.FromResult(entities);
    }

.Net fiddle .

请注意,任何手册代码应该使用缩进和未缩进的XML进行单元测试,因为在解析缩进的XML时,涉及跳过节点的错误有时会被掩盖(因为会跳过空白节点)