合并XML文档至SOAP信封时遇System.ArgumentException问题求助

我们使用的API允许<Transaction>标签下包含多个<Message>及其他配置项。<Message>标签及其子节点是随任务变化的部分，因此将其独立存放在XmlDocument中，尝试合并回SOAP信封的<Transaction>节点时，调用AppendChild方法抛出异常：

System.ArgumentException: 'The node to be inserted is from a different document context.'

相关代码 #

生成SOAP信封的代码 #

public XmlDocument SoapRequestEnvelope()
{
    XmlDocument envelope = new XmlDocument();
    envelope.LoadXml(@"\n        <?xml version=\"1.0\" encoding=\"utf-8\"?>\n        <soap:Envelope xmlns:soap=\"http://www.w3.org/2003/05/soap-envelope\" xmlns:tyl=\"http://www.VendorWeb.com\" xmlns:wsa=\"http://schemas.xmlsoap.org/ws/2004/08/addressing\" xmlns:wsse=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd\" xmlns:wsu=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd\">\n            <soap:Header>\n                <wsa:To>https://test.VendorAccess.cloud/ExternalWebService/TranslationBridgeExternalService.asmx</wsa:To>\n                <wsa:Action>http://www.MyVendor.com/VendorApiTxnExecutionSyncXml</wsa:Action>\n                <wsse:Security soap:mustUnderstand=\"1\">\n                    <wsu:Timestamp wsu:Id =\"Timestamp -Redacted\">\n                    <wsu:Created>2018-01-10T00:00:00Z</wsu:Created>\n                    <wsu:Expires>2023-03-31T23:59:59Z</wsu:Expires>\n                    </wsu:Timestamp>\n                    <wsse:UsernameToken wsu:Id=\"SecurityToken-Redacted\">\n                    <wsse:Username>UserName</wsse:Username>\n                    <wsse:Password Type=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText\">PASSWORD</wsse:Password>\n                    </wsse:UsernameToken>\n                </wsse:Security>\n                <tyl:ApiMessageContext>\n                    <tyl:SystemEnvironment>MySiteTest</tyl:SystemEnvironment>\n                    <tyl:RetryCount> 0 </tyl:RetryCount>\n                    <tyl:AllowFaults> true </tyl:AllowFaults>\n                </tyl:ApiMessageContext>\n            </soap:Header>\n            <soap:Body>\n                <tyl:ApiTxnExecutionSyncXml>\n                    <tyl:apiMessageData>\n                        <Transaction ReferenceNumber=\"IKJT1\" Source=\"IKJT\" TransactionType=\"IKJTEx\" >\n                            <Message MessageType=\"FindCase\" NodeID=\"12\" ReferenceNumber=\"R-19293\" UserID=\"5235126\" Source=\"Vendor\">\n                                <Options>\n                                    <Nodes>\n                                        <All>True</All>\n                                    </Nodes>\n                                    <CaseCategories>\n                                        <All>True</All>\n                                    </CaseCategories>\n                                    <CaseTypes>\n                                        <All>True</All>\n                                    </CaseTypes>\n                                </Options>\n                                <SearchCriteria>\n                                    <Case>\n                                        <CaseNumber>123456</CaseNumber>\n                                    </Case>\n                                </SearchCriteria>\n                            </Message>\n                        </Transaction>\n                    </tyl:apiMessageData>\n                </tyl:ApiTxnExecutionSyncXml>\n            </soap:Body>\n        </soap:Envelope>\n    ");
    
    return envelope;
}

生成独立Message的代码 #

public XmlDocument SOAPReqBody()
{
    XmlDocument body = new XmlDocument();
    body.LoadXml(
        @"<Message MessageType=\"Config\">\n            <Options>\n                <Nodes>\n                    <All>True</All>\n                </Nodes>\n            </Options>\n            <SearchCriteria>\n                <Case>\n                    <CaseNumber>125487</CaseNumber>\n                </Case>\n            </SearchCriteria>\n        </Message>"
    );

    return body;
}

原合并代码 #

public XmlDocument CallXML()
{
    XmlDocument envelope = SoapRequestEnvelope();
    XmlDocument body = SOAPReqBody();
    XmlNode bodyNode = body.DocumentElement;
    XmlNode envelopeNode = envelope.SelectSingleNode("descendant::Transaction");
    XmlElement root = envelope.DocumentElement;

    Console.WriteLine(envelopeNode);
    envelopeNode.AppendChild(bodyNode);

    return (envelope);
}

异常的核心是：不同XmlDocument实例的节点无法直接操作。bodyNode属于SOAPReqBody()创建的文档实例，envelopeNode属于SoapRequestEnvelope()创建的另一个文档实例，二者上下文不匹配，直接调用AppendChild会触发异常。

使用XmlDocument.ImportNode()方法将外部节点导入到目标文档的上下文，该方法会创建一个适配当前文档的节点副本，之后即可正常添加到目标节点下。

针对长期目标（将信封XML移至外部文件加载），只需将envelope.LoadXml()替换为envelope.Load("路径/信封文件.xml")即可，合并逻辑无需修改。

修改后的合并代码 #

public XmlDocument CallXML()
{
    XmlDocument envelope = SoapRequestEnvelope();
    XmlDocument body = SOAPReqBody();
    XmlNode bodyNode = body.DocumentElement;
    XmlNode envelopeNode = envelope.SelectSingleNode("descendant::Transaction");

    // 关键步骤：导入外部节点到当前文档上下文，第二个参数true表示递归导入所有子节点
    XmlNode importedNode = envelope.ImportNode(bodyNode, true);
    envelopeNode.AppendChild(importedNode);

    return envelope;
}

添加多个Message节点的示例 #

如果需要添加多个<Message>，重复执行导入-添加流程即可：

public XmlDocument CallXMLWithMultipleMessages()
{
    XmlDocument envelope = SoapRequestEnvelope();
    XmlNode transactionNode = envelope.SelectSingleNode("descendant::Transaction");

    // 添加第一个Message
    XmlDocument msg1Doc = SOAPReqBody();
    XmlNode importedMsg1 = envelope.ImportNode(msg1Doc.DocumentElement, true);
    transactionNode.AppendChild(importedMsg1);

    // 添加第二个Message（假设有另一个生成Message的方法）
    XmlDocument msg2Doc = GetAnotherMessage();
    XmlNode importedMsg2 = envelope.ImportNode(msg2Doc.DocumentElement, true);
    transactionNode.AppendChild(importedMsg2);

    return envelope;
}

// 示例：生成另一个Message的方法
public XmlDocument GetAnotherMessage()
{
    XmlDocument doc = new XmlDocument();
    doc.LoadXml(@"<Message MessageType=\"UpdateCase\">\n            <CaseData>\n                <CaseNumber>765432</CaseNumber>\n                <Status>Closed</Status>\n            </CaseData>\n        </Message>");
    return doc;
}

内容的提问来源于stack exchange，提问作者BenStark