How could I find the string position (index) from an XPath statement?

Question

This question is close, but it's looking for the ordinal position. I'm looking for the actual index position in a given source string.

Better Explanation:

I have the following string

"<a>
    <b>zyx</b>
    <b>wvu</b>
    <b>tsr</b>
    <b>qpo</b>
</a>"

I'm loading that string into a .NET XmlDocument object. Carriage Returns and Line Fees may be a factor here.

Dim xmlSearchText As New XmlDocument()
xmlSearchText.LoadXml(SearchTextBox.Text)

Dim selectedNode As XmlNode = xmlSearchText.SelectSingleNode(txtSearch.Text)

The following XPath Statement could be used to find the 3rd node:

a/b[.='tsr']

However, I need it to return a string index of 23 rather than the ordinal position of 3.

Possible? Not Possible?

I'm thinking the index of first greater-than character. So OuterXml of the selected node would be appropriate. — Joshua Hayworth, May 07 '09 at 19:28

Crispy · Accepted Answer · 2009-05-07T19:34:41.143

0

Does this give you what you want?

selectedNodenode = xmlSearchText.SelectSingleNode("a/b[.='tsr']");
selectedNode.ParentNode.OuterXml.IndexOf(selectedNode.OuterXml)

Won't give you the index from the root, but it'll give you the index from the parent node.

edited May 07 '09 at 19:34

answered May 07 '09 at 19:19

Crispy

5,557
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It gets me pretty darn close. I'm currently using (as of the time of this comment) SearchTextBox.Text.IndexOf(selectedNode.OuterXml) – Joshua Hayworth May 07 '09 at 19:31

Coincoin · Answer 2 · 2009-05-07T20:36:24.800

Using XPathDocument instead of XmlDocument will let you access the IXmlLineInfo interface with line number and column position.

XPathDocument document = new XPathDocument("file.xml");
XPathNavigator navigator = document.CreateNavigator();
XPathNavigator node = navigator.Select("a/b[.='tsr']");
IXmlLineInfo info = ((IXmlLineInfo)node);
Console.WriteLine("Found at ({0},{1})",info.LineNumber,info.LinePosition);

If you really need the character index from the string, you can deduce it by counting newlines int the string and adding the column.

How could I find the string position (index) from an XPath statement?

2 Answers2