将datatable或dataset添加到现有XML节点

我有这样一个XML

<?xml version="1.0" standalone="yes"?>
<Claim.Submission>
  <Header>
    <SenderID>DHA123</SenderID>
    <ReceiverID>A002</ReceiverID>
    <TransactionDate>2012-07-05T15:00:00+05:30</TransactionDate>
    <RecordCount>3</RecordCount>
    <DispositionFlag>PRODUCTION</DispositionFlag>
  </Header>
  <Claim>
    <ID>123</ID>
    <MemberID>m01254</MemberID>
    <PayerID>A002</PayerID>
    <ProviderID>DHA123</ProviderID>
    <EmiratesIDNumber>111-1111-1111111-1</EmiratesIDNumber>
    <Gross>100</Gross>
    <PatientShare>0</PatientShare>
    <Net>100</Net>
  </Claim>
 </Claim.Submission>

DHA123
A002
2012-07-05T15:00:00+05:30
3.
生产
123
m01254
A002
DHA123
111-1111-1111111-1
100
0
100

但是我想在

节点中动态添加一个数据表。ie；我希望XML作为

<?xml version="1.0" standalone="yes"?>
<Claim.Submission>
  <Header>
    <SenderID>DHA123</SenderID>
    <ReceiverID>A002</ReceiverID>
    <TransactionDate>2012-07-05T15:00:00+05:30</TransactionDate>
    <RecordCount>3</RecordCount>
    <DispositionFlag>PRODUCTION</DispositionFlag>
  </Header>
  <Claim>
    <ID>123</ID>
    <MemberID>m01254</MemberID>
    <PayerID>A002</PayerID>
    <ProviderID>DHA123</ProviderID>
    <EmiratesIDNumber>111-1111-1111111-1</EmiratesIDNumber>
    <Gross>100</Gross>
    <PatientShare>0</PatientShare>
    <Net>100</Net>
  <Encounter>
    <FacilityID>DHA123</FacilityID>
    <Type>3</Type>
    <PatientID>1245</PatientID>
    <Start>2012-01-01T12:00:00+05:30</Start>
    <End>2012-01-05T15:00:00+05:30</End>
    <StartType>1</StartType>
    <EndType>1</EndType>
  </Encounter>
 </Claim>
</Claim.Submission>

DHA123
A002
2012-07-05T15:00:00+05:30
3.
生产
123
m01254
A002
DHA123
111-1111-1111111-1
100
0
100
DHA123
3.
1245
2012-01-01T12:00:00+05:30
2012-01-05T15:00:00+05:30
1.
1.

您可以尝试使用XmlTextWriter类写入XML文件：

---

如果要写入现有文件，它将用指定的内容替换文件内容，因此请确保正确更新记录，否则可能会丢失存储的信息

我是新来的，所以请附上样品。我有许多数据表要添加到不同的节点，所以我想选择指定的节点。