Simple Xpath question

[Ot]

I posted this to the wrong group. It went to m.p.dotnet.lang uages.vb.
Ooops.

--------------------------------------------------------------------

I have this tiny problem. I have learned that an xpath expression can be
bounded by either single or double quotation marks.

But sometimes I want to search for a title containing both a single and
double quote. Any way to do this?

The user enters the title, so now it is in a String variable.

How can I dynamically construct the right Xpath query to find the book with
that title.

<book>
<title>Who's your "Daddy"</title>


The only logic that I can think of is to detect the occurrence of double
quotes in the data and make an iterator that finds the partial title (the
part that doesn't contain the ' " ') and then do an individual match title
by title.

[Martin Honnen]

Re: Simple Xpath question



Ot wrote:

[color=blue]
> I have this tiny problem. I have learned that an xpath expression can be
> bounded by either single or double quotation marks.
>
> But sometimes I want to search for a title containing both a single and
> double quote. Any way to do this?
>
> The user enters the title, so now it is in a String variable.
>
> How can I dynamically construct the right Xpath query to find the book with
> that title.
>
> <book>
> <title>Who's your "Daddy"</title>
>
>
> The only logic that I can think of is to detect the occurrence of double
> quotes in the data and make an iterator that finds the partial title (the
> part that doesn't contain the ' " ') and then do an individual match title
> by title.[/color]

Here is an example C# program that breaks up a string as needed to
construct an XPath concat function call

using System;
using System.Xml;

public class Test20040125 {
public static void Main (string[] args) {
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.Loa dXml(
@"<book><title> Who's your ""Daddy""</title></book>");
string userInput = @"Who's your ""Daddy""";
XmlElement title = xmlDocument.Sel ectSingleNode("//title[. = " +
buildXPathStrin g(userInput) + "]") as XmlElement;
if (title != null) {
Console.WriteLi ne(title.OuterX ml);
}
else {
Console.WriteLi ne("No element found.");
}
}

public static string buildXPathStrin g (string input) {
string[] components = input.Split(new char[] { '\''});
string result = "";
result += "concat(''" ;
for (int i = 0; i < components.Leng th; i++) {
result += ", '" + components[i] + "'";
if (i < components.Leng th - 1) {
result += ", \"'\"";
}
}
result += ")";
Console.WriteLi ne(result);
return result;
}
}


The example constructs
concat('', 'Who', "'", 's your "Daddy"')
as the XPath concat call so you see that the string is split up into
parts not containing a single quote and parts just containing the single
quote.
--

Martin Honnen

http://JavaScript.FAQTs.com/

[Ot]

Re: Simple Xpath question (html for readability)

"Martin Honnen" <Martin.Honnen@ t-online.de> wrote in message news:%23PzSut14 DHA.2392@TK2MSF TNGP11.phx.gbl. ..[color=blue]
>
> Here is an example C# program that breaks up a string as needed to
> construct an XPath concat function call
>
> using System;
> using System.Xml;
>
> public class Test20040125 {
> public static void Main (string[] args) {
> XmlDocument xmlDocument = new XmlDocument();
> xmlDocument.Loa dXml(
> @"<book><title> Who's your ""Daddy""</title></book>");
> string userInput = @"Who's your ""Daddy""";
> XmlElement title = xmlDocument.Sel ectSingleNode("//title[. = " +
> buildXPathStrin g(userInput) + "]") as XmlElement;
> if (title != null) {
> Console.WriteLi ne(title.OuterX ml);
> }
> else {
> Console.WriteLi ne("No element found.");
> }
> }
>
> public static string buildXPathStrin g (string input) {
> string[] components = input.Split(new char[] { '\''});
> string result = "";
> result += "concat(''" ;
> for (int i = 0; i < components.Leng th; i++) {
> result += ", '" + components[i] + "'";
> if (i < components.Leng th - 1) {
> result += ", \"'\"";
> }
> }
> result += ")";
> Console.WriteLi ne(result);
> return result;
> }
> }
>
>
> The example constructs
> concat('', 'Who', "'", 's your "Daddy"')
> as the XPath concat call so you see that the string is split up into
> parts not containing a single quote and parts just containing the single
> quote.
> --
>
> Martin Honnen
> http://JavaScript.FAQTs.com/
> [/color]

Thanks for your input. I did my best to reconstruct what you wrote in an equivalent VB.NET program. (I made it react to a button-click, but it is really no different.) Thing is, it gets an exception. Can you figure out why? I'm really confused here.

\\\
Private Sub Button1_Click(B yVal sender As Object, ByVal e As System.EventArg s) Handles Button1.Click
Dim xmlDocument As XmlDocument = New XmlDocument
xmlDocument.Loa dXml("<book><ti tle>Who's your ""Daddy""</title></book>")
Dim sw As IO.StreamWriter = New System.IO.Strea mWriter("C:\tes tbook.xml")
Dim xm As System.Xml.XmlT extWriter = New System.Xml.XmlT extWriter(sw)
xm.Formatting = Formatting.Inde nted
xm.Indentation = 2
xm.IndentChar = " "
xmlDocument.Sav e(xm)
Dim userInput As String = "Who's your ""Daddy"""
Dim query As String = "//title[. = '" & buildXpathStrin g(userInput) & "']"
Console.WriteLi ne("query={" & query & "}")
Dim title As XmlElement = _
xmlDocument.Sel ectSingleNode(q uery)
If title Is Nothing Then
Console.WriteLi ne("No Element found.")
Else
Console.WriteLi ne("Title=" & title.OuterXml)
End If
End Sub
Function buildXpathStrin g(ByVal input As String) As String
Dim components() As String = input.Split("'" c)
Dim result As String = ""
For i As Integer = 0 To components.Leng th - 2
result += components(i) & "''"
Next
result += components(comp onents.Length - 1)
Console.WriteLi ne("result={" & result & "}")
Return result
End Function
///

has as output

\\\
result={Who''s your "Daddy"}
query={//title[. = 'Who''s your "Daddy"']}
An unhandled exception of type 'System.Xml.XPa th.XPathExcepti on' occurred in system.xml.dll
Additional information: System error.
Unhandled Exception: System.Xml.XPat h.XPathExceptio n: '//title[. = 'Who''s your "Daddy"']' has an invalid token.
///

The contents of testbook.xml file is

\\\
<?xml version="1.0" encoding="utf-8"?>
<book>
<title>Who's your "Daddy"</title>
</book>
///

[Ot]

Re: Simple Xpath question


"Martin Honnen" <Martin.Honnen@ t-online.de> wrote in message
news:%23PzSut14 DHA.2392@TK2MSF TNGP11.phx.gbl. ..[color=blue]
>
>
> Ot wrote:
>
>[color=green]
> > I have this tiny problem. I have learned that an xpath expression can[/color][/color]
be[color=blue][color=green]
> > bounded by either single or double quotation marks.
> >
> > But sometimes I want to search for a title containing both a single and
> > double quote. Any way to do this?
> >
> > The user enters the title, so now it is in a String variable.
> >
> > How can I dynamically construct the right Xpath query to find the book[/color][/color]
with[color=blue][color=green]
> > that title.
> >
> > <book>
> > <title>Who's your "Daddy"</title>
> >
> >
> > The only logic that I can think of is to detect the occurrence of[/color][/color]
double[color=blue][color=green]
> > quotes in the data and make an iterator that finds the partial title[/color][/color]
(the[color=blue][color=green]
> > part that doesn't contain the ' " ') and then do an individual match[/color][/color]
title[color=blue][color=green]
> > by title.[/color]
>
> Here is an example C# program that breaks up a string as needed to
> construct an XPath concat function call
>
> using System;
> using System.Xml;
>
> public class Test20040125 {
> public static void Main (string[] args) {
> XmlDocument xmlDocument = new XmlDocument();
> xmlDocument.Loa dXml(
> @"<book><title> Who's your ""Daddy""</title></book>");
> string userInput = @"Who's your ""Daddy""";
> XmlElement title = xmlDocument.Sel ectSingleNode("//title[. = " +
> buildXPathStrin g(userInput) + "]") as XmlElement;
> if (title != null) {
> Console.WriteLi ne(title.OuterX ml);
> }
> else {
> Console.WriteLi ne("No element found.");
> }
> }
>
> public static string buildXPathStrin g (string input) {
> string[] components = input.Split(new char[] { '\''});
> string result = "";
> result += "concat(''" ;
> for (int i = 0; i < components.Leng th; i++) {
> result += ", '" + components[i] + "'";
> if (i < components.Leng th - 1) {
> result += ", \"'\"";
> }
> }
> result += ")";
> Console.WriteLi ne(result);
> return result;
> }
> }
>
>
> The example constructs
> concat('', 'Who', "'", 's your "Daddy"')
> as the XPath concat call so you see that the string is split up into
> parts not containing a single quote and parts just containing the single
> quote.
> --
>
> Martin Honnen
> http://JavaScript.FAQTs.com/
>[/color]

Thanks for your input. I did my best to reconstruct what you wrote in an
equivalent VB.NET program. (I made it react to a button-click, but it is
really no different.) Thing is, it gets an exception. Can you figure out
why? I'm really confused here.

\\\
Private Sub Button1_Click(B yVal sender As Object, ByVal e As
System.EventArg s) Handles Button1.Click
Dim xmlDocument As XmlDocument = New XmlDocument
xmlDocument.Loa dXml("<book><ti tle>Who's your
""Daddy""</title></book>")
Dim sw As IO.StreamWriter = New
System.IO.Strea mWriter("C:\tes tbook.xml")
Dim xm As System.Xml.XmlT extWriter = New
System.Xml.XmlT extWriter(sw)
xm.Formatting = Formatting.Inde nted
xm.Indentation = 2
xm.IndentChar = " "
xmlDocument.Sav e(xm)
Dim userInput As String = "Who's your ""Daddy"""
Dim query As String = "//title[. = '" & buildXpathStrin g(userInput)
& "']"
Console.WriteLi ne("query={" & query & "}")
Dim title As XmlElement = _
xmlDocument.Sel ectSingleNode(q uery)
If title Is Nothing Then
Console.WriteLi ne("No Element found.")
Else
Console.WriteLi ne("Title=" & title.OuterXml)
End If
End Sub
Function buildXpathStrin g(ByVal input As String) As String
Dim components() As String = input.Split("'" c)
Dim result As String = ""
For i As Integer = 0 To components.Leng th - 2
result += components(i) & "''"
Next
result += components(comp onents.Length - 1)
Console.WriteLi ne("result={" & result & "}")
Return result
End Function
///

has as output

\\\
result={Who''s your "Daddy"}
query={//title[. = 'Who''s your "Daddy"']}
An unhandled exception of type 'System.Xml.XPa th.XPathExcepti on' occurred
in system.xml.dll
Additional information: System error.
Unhandled Exception: System.Xml.XPat h.XPathExceptio n: '//title[. = 'Who''s
your "Daddy"']' has an invalid token.
///

The contents of testbook.xml file is

\\\
<?xml version="1.0" encoding="utf-8"?>
<book>
<title>Who's your "Daddy"</title>
</book>
///

[Martin Honnen]

Re: Simple Xpath question



Ot wrote:
[color=blue]
> "Martin Honnen" <Martin.Honnen@ t-online.de> wrote in message[/color]
[color=blue][color=green]
>>Here is an example C# program that breaks up a string as needed to
>>construct an XPath concat function call
>>
>>using System;
>>using System.Xml;
>>
>>public class Test20040125 {
>> public static void Main (string[] args) {
>> XmlDocument xmlDocument = new XmlDocument();
>> xmlDocument.Loa dXml(
>>@"<book><titl e>Who's your ""Daddy""</title></book>");
>> string userInput = @"Who's your ""Daddy""";
>> XmlElement title = xmlDocument.Sel ectSingleNode("//title[. = " +
>>buildXPathStr ing(userInput) + "]") as XmlElement;
>> if (title != null) {
>> Console.WriteLi ne(title.OuterX ml);
>> }
>> else {
>> Console.WriteLi ne("No element found.");
>> }
>> }
>>
>> public static string buildXPathStrin g (string input) {
>> string[] components = input.Split(new char[] { '\''});
>> string result = "";
>> result += "concat(''" ;
>> for (int i = 0; i < components.Leng th; i++) {
>> result += ", '" + components[i] + "'";
>> if (i < components.Leng th - 1) {
>> result += ", \"'\"";
>> }
>> }
>> result += ")";
>> Console.WriteLi ne(result);
>> return result;
>> }
>>}
>>
>>
>>The example constructs
>> concat('', 'Who', "'", 's your "Daddy"')
>>as the XPath concat call so you see that the string is split up into
>>parts not containing a single quote and parts just containing the single
>>quote.[/color][/color]
[color=blue]
>
> Thanks for your input. I did my best to reconstruct what you wrote in an
> equivalent VB.NET program. (I made it react to a button-click, but it is
> really no different.) Thing is, it gets an exception. Can you figure out
> why? I'm really confused here.
>[/color]
[color=blue]
> Function buildXpathStrin g(ByVal input As String) As String
> Dim components() As String = input.Split("'" c)
> Dim result As String = ""
> For i As Integer = 0 To components.Leng th - 2
> result += components(i) & "''"
> Next
> result += components(comp onents.Length - 1)
> Console.WriteLi ne("result={" & result & "}")
> Return result
> End Function[/color]

The suggested solution is to construct some XPath expression with a
concat(...)
function call which the C# method above does while your VB.NET method
doesn't do that.
--

Martin Honnen

http://JavaScript.FAQTs.com/

[Ot]

Re: Simple Xpath question


"Martin Honnen" <Martin.Honnen@ t-online.de> wrote in message
news:eehOoQC5DH A.1636@TK2MSFTN GP12.phx.gbl...[color=blue]
>[color=green]
> > The suggested solution is to construct some XPath expression with a[/color]
> concat(...)
> function call which the C# method above does while your VB.NET method
> doesn't do that.
> --
>
> Martin Honnen
> http://JavaScript.FAQTs.com/
>[/color]

Forgive my confusion, but isn't a string a string regardless of how it is
constructed? Isn't this an Xpath issue now, not a programming issue?
Doesn't your C# program eventually issue the same Xpath query? It seems to
me it does, hence my confusion.

As you can see from my quoted output I get

query={//title[. = 'Who''s your "Daddy"']}

(the '{' and '}' I put in just to show the extent of the string, they are
not part of the string itself.)

then I do

Dim title As XmlElement = _
xmlDocument.Sel ectSingleNode(q uery)

and the error occurs.

Thanks for taking your time to help me with this, it is appreciated.

[Martin Honnen]

Re: Simple Xpath question



Ot wrote:
[color=blue]
> "Martin Honnen" <Martin.Honnen@ t-online.de> wrote in message
> news:eehOoQC5DH A.1636@TK2MSFTN GP12.phx.gbl...
>[color=green][color=darkred]
>>>The suggested solution is to construct some XPath expression with a[/color]
>>
>> concat(...)
>>function call which the C# method above does while your VB.NET method
>>doesn't do that.[/color][/color]
[color=blue]
>
> Forgive my confusion, but isn't a string a string regardless of how it is
> constructed? Isn't this an Xpath issue now, not a programming issue?
> Doesn't your C# program eventually issue the same Xpath query? It seems to
> me it does, hence my confusion.
>
> As you can see from my quoted output I get
>
> query={//title[. = 'Who''s your "Daddy"']}[/color]

Yes, but that doesn't work, you need to construct the XPath expression
//title[. = concat('Who', "'", 's your "Daddy"')]
--

Martin Honnen

http://JavaScript.FAQTs.com/

[Ot]

Re: Simple Xpath question


"Martin Honnen" <Martin.Honnen@ t-online.de> wrote in message
news:eeP1tUD5DH A.2656@TK2MSFTN GP11.phx.gbl...[color=blue]
>
>
> Ot wrote:
>[color=green]
> > "Martin Honnen" <Martin.Honnen@ t-online.de> wrote in message
> > news:eehOoQC5DH A.1636@TK2MSFTN GP12.phx.gbl...
> >[color=darkred]
> >>>The suggested solution is to construct some XPath expression with a
> >>
> >> concat(...)
> >>function call which the C# method above does while your VB.NET method
> >>doesn't do that.[/color][/color]
>[color=green]
> >
> > Forgive my confusion, but isn't a string a string regardless of how it[/color][/color]
is[color=blue][color=green]
> > constructed? Isn't this an Xpath issue now, not a programming issue?
> > Doesn't your C# program eventually issue the same Xpath query? It[/color][/color]
seems to[color=blue][color=green]
> > me it does, hence my confusion.
> >
> > As you can see from my quoted output I get
> >
> > query={//title[. = 'Who''s your "Daddy"']}[/color]
>
> Yes, but that doesn't work, you need to construct the XPath expression
> //title[. = concat('Who', "'", 's your "Daddy"')]
> --
>
> Martin Honnen
> http://JavaScript.FAQTs.com/
>[/color]

Ah, dawns the light!

Thanks for your help!