自动格式化长outerXml字符串

Question

我有多个大型XML文件，并试图提取特定元素及其子元素的5个实例。我已经设置了所有的代码，但是，我必须使用StreamWriter来写出xml。我怎么做才能使它正确缩进，等等。

字符串看起来像这样:

<SampleMAIN><Sample type="1"><Sample_Batch>123
</Sample_Batch><SampleMethod>
</SampleMethod>
</Sample></SampleMAIN>

我想让它看起来像这样:

<SampleMAIN>
    <Sample type="1">
        <Sample_Batch>123
    </Sample_Batch>
        <SampleMethod>1
    </SampleMethod>
</SampleMAIN>

Answer 1

使用StreamWriter，下面的代码将输出所需的格式，并将其附加到现有的xml文件中。

Private Sub Button1_Click(sender As System.Object, _
                          e As System.EventArgs) Handles Button1.Click
    Dim sw As System.IO.StreamWriter
    Dim St As String = "1"
    Dim Sb As String = "123"
    Dim Sm As String = "1"
    sw = File.AppendText("C:XML_Filessampler_02.xml")
    sw.WriteLine("<SampleMAIN>")
    sw.WriteLine("    <Sample type=" & """" & St & """" & ">")
    sw.WriteLine("        <Sample_Batch>" & Sb)
    sw.WriteLine("    </Sample_Batch>")
    sw.WriteLine("        <SampleMethod>" & Sm)
    sw.WriteLine("    </SampleMethod>")
    sw.WriteLine("</SampleMAIN>")
    sw.Close()
End Sub

Answer 2

对于任何可能遇到这个问题并对我如何解决它感兴趣的人，以下是我使用的…

    Dim dir As New DirectoryInfo("D:data")
    Dim sw As New StreamWriter("C:DocumentslargeFile.xml")
    Dim xd As New XmlDocument
    Dim iCount As Integer
    sw.WriteLine("<?xml version=""1.0"" encoding=""ISO-8859-1""?>" & vbCrLf & "<Root>")
    For Each fi As FileInfo In dir.GetFiles()
        xd.Load(fi.FullName)
        iCount = 0
        For Each xn As XmlNode In xd.SelectNodes("//Root")          
            For Each xe As XmlElement In xn.ChildNodes
                iCount += 1
                sw.WriteLine(xe.OuterXml.ToString)
                If iCount = 5 Then Exit For
            Next
            Exit For
        Next
    Next
    sw.WriteLine("</Root>")
    sw.Flush() : sw.Close() : sw.Dispose()