通过Linq C＃通过Xdocument更新XML

Question

我正在使用C＃中的Xdocument来操纵以下XML文档的更精细版本。我正在尝试检查每个部分的“零件”元素值是否为99999。如果值为99999，我想将整个零件元素交换为我存储在字符串变量中的新零件元素。

<statement>   
    <header>
        <created>5/3/2022</created>        
        <charges>100.00</charges>        
        <description>some text</description>
        <billing-party>
            <name>3304</name>
            <address>1703</address>
            <phone />
        </billing-party>      
    </header>    
    <invoices>
        <invoice>
            <invoice-no>39D5</invoice-no>
            <line-items>
                <line-item>
                    <line-no>1</line-no>                    
                    <parts>
                        <part>
                            <part-no>990303</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                        <part>
                            <part-no>890304</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                    </parts>                    
                    <part-number>139186</part-number>
                </line-item>
                <line-item>
                    <line-no>2</line-no>                    
                    <parts>
                        <part>
                            <part-no>990303</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                        <part>
                            <part-no>890304</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                    </parts>                    
                    <part-number>139186</part-number>
                </line-item>
                <line-item>
                    <line-no>1</line-no>                    
                    <parts>
                        <part>
                            <part-no>990303</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                        <part>
                            <part-no>890304</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                    </parts>                    
                    <part-number>139186</part-number>
                </line-item>               
            </line-items>
        </invoice>
        <invoice>
            <invoice-no>39D5</invoice-no>
            <line-items>
                <line-item>
                    <line-no>1</line-no>                    
                    <parts>
                        <part>
                            <part-no>990303</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                        <part>
                            <part-no>890304</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                    </parts>                    
                    <part-number>139186</part-number>
                </line-item>
                <line-item>
                    <line-no>2</line-no>                    
                    <parts>
                        <part>
                            <part-no>990303</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                        <part>
                            <part-no>890304</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                    </parts>                    
                    <part-number>139186</part-number>
                </line-item>
                <line-item>
                    <line-no>1</line-no>                    
                    <parts>
                        <part>
                            <part-no>99999</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                        <part>
                            <part-no>890304</part-no>
                            <description>
                               some description
                            </description>
                            <tax />
                            <value>270.50</value>
                            <quantity />                            
                        </part>
                    </parts>                    
                    <part-number>139186</part-number>
                </line-item>               
            </line-items>
        </invoice>
    </invoices>
</statement>

使用LINQ，在不创建新的Xdocument的情况下执行此操作的最佳方法是什么？

我尝试了这一点，但是我是Linq的新手，并且不太了解如何在不使用FirstOrdOdefault（）的情况下实现这一目标。

statementFile.ReplaceNodes(

                from invoice in statementFile.Descendants("invoices")
                from lineItem in invoice.Descendants("line-items")
                from part in lineItem.Descendants("parts")
                where part.Element("part-no").Value.Equals("99999")
                select part.ReplaceWith(updatedPart));    
                );