将数据添加到现有的XML文件

Question

这是我追加新记录，以我现有的XML文档代码：

Sub addEXISTING(ByVal c_name As String, ByVal c_age As Integer, ByVal c_sex As String) 
    Dim e_client = doc.CreateElement("CLIENT") 

    Dim e_name As Xml.XmlElement = doc.CreateElement("NAME") 

    Dim e_age As Xml.XmlElement = doc.CreateElement("AGE") 

    Dim e_sex As Xml.XmlElement = doc.CreateElement("SEX") 

    e_name.InnerText = c_name 
    e_age.InnerText = c_age 
    e_sex.InnerText = c_sex 
    e_client.AppendChild(e_name) 
    e_client.AppendChild(e_age) 
    e_client.AppendChild(e_sex) 
    childparent.AppendChild(e_client) 

    doc.AppendChild(childparent) 
    doc.Save("D:\mefolder\me.xml") 
    MsgBox("XML DOCUMENT UPDATED!", MsgBoxStyle.Information, "Notice:") 
End Sub 

但执行这段代码当过，新的数据的文件条目将覆盖现有的那些。

基本上，我想输出是这样的，例如（观察在浏览器的XML文档时）：

<BIO_INFO> 
<CLIENT> ----- EXISTING 
<NAME>John</NAME> 
<AGE>21</AGE> 
<SEX>MALE</SEX> 
</CLIENT> 
<CLIENT> ----- NEW ENTRY 
<NAME>Elena</NAME> 
<AGE>21</AGE> 
<SEX>FEMALE</SEX> 
</CLIENT> 
</BIO_INFO> 

但是，这是我所得到的：

<BIO_INFO> 
<CLIENT> 
<NAME>Elena</NAME> 
<AGE>21</AGE> 
<SEX>FEMALE</SEX> 
</CLIENT> 
</BIO_INFO>" 

这里有我的声明：

Dim filer As DirectoryInfo = New DirectoryInfo("D:\mefolder") 
Dim doc As New XmlDocument 
Dim root As XmlElement = doc.CreateElement("CLIENT") 
Dim childparent As XmlElement = doc.CreateElement("BIO_INFO") 
Dim child As XmlElement = doc.CreateElement("NAME") 
Dim childage As XmlElement = doc.CreateElement("AGE") 
Dim childsex As XmlElement = doc.CreateElement("SEX") 

Answer 1

不可能将数据附加到xml文档。您需要加载整个文档并再次保存（从nianios注释Appending an existing XML file）。这是需要使用XmlDocument.Load Method

Sub addEXISTING(ByVal c_name As String, ByVal c_age As Integer, ByVal c_sex As String) 

    XmlDocument.Load("D:\mefolder\me.xml")'! 

    Dim e_client = doc.CreateElement("CLIENT") 
    Dim e_name As Xml.XmlElement = doc.CreateElement("NAME") 
    Dim e_age As Xml.XmlElement = doc.CreateElement("AGE") 
    Dim e_sex As Xml.XmlElement = doc.CreateElement("SEX") 

    e_name.InnerText = c_name 
    e_age.InnerText = c_age 
    e_sex.InnerText = c_sex 
    e_client.AppendChild(e_name) 
    e_client.AppendChild(e_age) 
    e_client.AppendChild(e_sex) 
    childparent.AppendChild(e_client) 

    doc.AppendChild(childparent) 
    doc.Save("D:\mefolder\me.xml") 
    MsgBox("XML DOCUMENT UPDATED!", MsgBoxStyle.Information, "Notice:") 
End Sub 

请注意，这种打开和保存对每条记录是不是很有效，尤其是当文件较大。考虑将.Save和.Load从您的方法中取出并单独触发它们（例如您正在文本编辑器中处理文本文件）。