我正在尝试从以下
XML结构获取PurchaseDate(来自
Windows Phone中的应用内购买的收据)：
<Receipt Version="1.0" CertificateId="..." xmlns="http://schemas.microsoft.com/windows/2012/store/receipt">
<ProductReceipt PurchasePrice="$0" PurchaseDate="2013-05-20T19:27:09.755Z" Id="..." AppId="..." ProductId="Unlock" ProductType="Consumable" PublisherUserId="..." PublisherDeviceId="..." MicrosoftProductId="..." />
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
<SignedInfo>
<CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
<SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256" />
<Reference URI="">
<Transforms>
<Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
</Transforms>
<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
<DigestValue>...</DigestValue>
</Reference>
</SignedInfo>
<SignatureValue>...</SignatureValue>
</Signature>
</Receipt>
我的代码如下：
XDocument doc = XDocument.Parse(receiptXml);
string date = doc.Root.Element("ProductReceipt").Attribute("PurchaseData").Value;
这会不断引发访问错误,因为doc.Root.Element(“ProductReceipt”)为null.为什么XDocument没有获得ProductReceipt元素？
解决方法
只需将命名空间添加到LINQ to XML查询中即可.因为您在根节点xmlns =“http://schemas.microsoft.com/windows/2012/store/receipt”上有默认名称空间声明,所以您还需要在查询中指定它.
XDocument doc = XDocument.Parse(receiptXml);
XNamespace xmlns = "http://schemas.microsoft.com/windows/2012/store/receipt";
string date = doc.Root
.Element(xmlns + "ProductReceipt")
.Attribute("PurchaseDate")
.Value;
Console.WriteLine(date);
打印：
2013-05-20T19:27:09.755Z
string date = doc.Root
.Elements()
.First(node => node.Name.LocalName == "ProductReceipt")
.Attribute("PurchaseDate")
.Value;
