No result of child nodes from xml C#

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I have an xml in which I am trying to grab every child node that start with the name title but only under a parent node named system and has an attribute equal to the value "28". So if the program sees title as a child node under the parent node system but system doesn't have an attribute that equals 28 then it will omit that child node.

public void node()
      {
          XmlTextReader reader = new XmlTextReader(@"C:\pg\ForFun\Node.xml");


          while (reader.Read())
          {

              if (reader.Name == "system")
              {


                  if (!(null == reader.GetAttribute("28")))

                  {
                      XmlReader inner = reader.ReadSubtree();
                      List<string> data = new List<string>();

                      while (inner.Read())
                      {
                          if (reader.Name == "title")
                          {
                              data.Add(reader.ReadString());
                          }
                      }
                      Console.WriteLine(data);
                  }

              }

          }
      }

This is my code when I run the program no error messages shows up however I just get a blank console screen. Appreciate any tips or suggestions

Here is a sample xml

XML

- <infotype infotypevalue="44" id="id4049">
  <infotypename>Removal and Installation</infotypename>
- <servinfo id="GUID-5FCEADFD-AFFA-4E01-B2C5-BA88E8325410">
  <title> Baggae Claims</title>
  <ptxt>GUID-5FCEADFD-AFFA-4E01-B2C5-BA88E8325410.xml</ptxt>
  </servinfo>
  </infotype>
  </component>
  </subsystem>
  </system>
- <system catnbr="28" id="id4051">
  <system-toc groupname="28" />
  <systemname>28 - Value Codes</systemname>
- <component compid="00088" id="id4052">
  <componentname>CLUSTER, Instrument</componentname>
- <infotype infotypevalue="03" id="id4053">
  <infotypename>Tester Class</infotypename>
- <servinfo id="GUID-F3F3BDA2-0DD4-4DD0-9E03-132CC780A889">
  <title>B1000-44-ELECTRONIC CONTROL UNIT - DATA MEMORY FAILURE</title>
  <ptxt>GUID-F3F3BDA2-0DD4-4DD0-9E03-132CC780A889.xml</ptxt>
  </servinfo>
- <servinfo id="GUID-6767D65E-FD48-465C-A304-6F4690C9D174">
  <title>B1000-45-ELECTRONIC CONTROL UNIT - PROGRAM MEMORY FOUND</title>
  <ptxt>GUID-6767D65E-FD48-465C-A304-6F4690C9D174.xml</ptxt>
  </servinfo>

Here is a sample output:
Only nodes under system that has attribute value "28" is selected

CLUSTER, Instrument

B1000-44-ELECTRONIC CONTROL UNIT - DATA MEMORY FAILURE

GUID-F3F3BDA2-0DD4-4DD0-9E03-132CC780A889

B1000-45-ELECTRONIC CONTROL UNIT - PROGRAM MEMORY FOUND

GUID-6767D65E-FD48-465C-A304-6F4690C9D174

Posted 2-Oct-15 2:40am

Member 12009796

Updated 2-Oct-15 11:37am

v2

Add a Solution

Comments

Maciej Los 2-Oct-15 16:01pm

What's your xml data? What's expected output?

Member 12009796 2-Oct-15 17:38pm

I have provided sample xml and sample output

Maciej Los 2-Oct-15 18:34pm

You xml is invalid! Provide complete data!

Member 12009796 2-Oct-15 18:59pm

It is a very large xmlfile that has unrelated data so that is why I only posted the segment of information that I am actually trying to grab.

Maciej Los 3-Oct-15 17:03pm

This piece of xml is incomplete (not well-formed). So, i can't provide a solution.

3 solutions

Solution 3

You can't use == to compare strings in C#, because it don't always behave as you expect.
Strictly speaking, if both strings are of type string, == works.
In your program, one part comes from an object and the exact type can be not the same.

http://stackoverflow.com/questions/1659097/why-would-you-use-string-equals-over[^]
http://csharp.net-informations.com/string/csharp-string-compare.htm[^]
http://stackoverflow.com/questions/44288/differences-in-string-compare-methods-in-c-sharp[^]
http://stackoverflow.com/questions/3678792/are-string-equals-and-operator-really-same[^]

Advice: use the debugger to see your code execute step by step, track variables.
The debugger will allow you to see what is doing your code and where/when it don't behave as expected.

PS: Looks like I was a little too fast at answering.

Posted 2-Oct-15 14:08pm

Patrice T

Updated 2-Oct-15 15:00pm

v4

Comments

Matt T Heffron 2-Oct-15 20:19pm

This is not true.
Even your second reference says so.
See also: https://msdn.microsoft.com/en-us/library/362314fe(v=vs.120).aspx

Patrice T 2-Oct-15 20:44pm

Looks like I was a little too quick :)
Is it better now ?

Matt T Heffron 2-Oct-15 20:52pm

reader.Name property is type string.
And it shouldn't be able to return null, so == should always work in this application.

Patrice T 2-Oct-15 21:04pm

Ok, and now?

Matt T Heffron 2-Oct-15 21:07pm

I think the key problem is what I noted in my Solution. The .GetAttribute("28") which won't do what is wanted.
Then the inner.Read() loop is wrong, etc.

Patrice T 2-Oct-15 21:12pm

I see.
In any case, the debugger allow to see where the program don't behave as expected, narrowing the research.

Matt T Heffron 2-Oct-15 21:14pm

Of course that's always the case.
Use the debugger to see what isn't happening the way one expects.

BillWoodruff 2-Oct-15 21:14pm

Set break-points, single-step through the code, inspect the values of variables.

Patrice T 2-Oct-15 21:17pm

Yes, I didn't detail debugger usage.

Solution 1

Try with Console.WriteLine(data.length + "");

-KR

Posted 2-Oct-15 2:49am

Krunal Rohit

Comments

Member 12009796 2-Oct-15 9:04am

Yeah but since data is declared under a list of string it wouldn't contain a definition for length unfortunately.

Matt T Heffron 2-Oct-15 21:45pm

How would concatenating the length of the List<string> (should be .Count) with an empty string display the strings in the list?

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Matt T Heffron · Accepted Answer · 2015-10-02T13:34:00

Solution 2

Since

C#

reader.GetAttribute("28")

doesn't get the attribute with a value of "28", I'm not surprised you get no output. It gets the attribute with the name of "28", and that wouldn't be a valid attribute name.
So find the correct type of element first.
Then get the attribute by the correct name.
Then check if its value is 28.

The inner.Read() loop should be using inner instead of reader:

C#

while (inner.Read())
{
  if (inner.Name == "title")
  {
    data.Add(inner.ReadString());
  }
}

Finally to write all the strings of a List<string> to the Console, try:

C#

data.ForEach(Console.WriteLine);

Posted 2-Oct-15 13:34pm

Matt T Heffron

Updated 2-Oct-15 14:56pm

v2

Comments

Member 12009796 3-Oct-15 13:34pm

Thanks Matt, the problem was the attribute values; once I found the attribute name then saved the value I was able to compile my code with the suggestion to write all the strings.

Matt T Heffron 5-Oct-15 11:44am

You're welcome.
Please formally "Accept Solution" using the green button above.

Member 12009796 9-Oct-15 8:56am

Sure no problem...data.Foreach(Console.WriteLine) works successful how can I make the output print to a textfile document the foreach causes problems when I try to use File.WriteAlltext

Matt T Heffron 9-Oct-15 13:21pm

Just use File.WriteAllLines("path", data);

Member 12009796 9-Oct-15 15:44pm

Okay perfect and I have one last question. When the program runs it starts reading/grabbing from the data I need but it also keeps reading/grabbing the data to the end rest of the file instead of it staying within the boundaries I want. I tried an else statement but caused a no return output.

XmlTextReader textFile = new XmlTextReader(@"\\Companynet\motordfs\eAcquisition\Chrysler\Service Information\2014\JS - Chrysler 200 & Dodge Avenger\Service_MDS2002si2014JSenUSsvf_Content_AppServer_20140403_1\clocal\www\web-data\service\mds2002\toc\SI2014JSen_US.xml");
string value = null;
string idValue = "";

while (textFile.Read())
{
textFile.MoveToContent();

if (textFile.Name == "system")
{
value = textFile.GetAttribute("catnbr");

if (value == "28")

{
List<string> dtc = new List<string>();

while (textFile.Read())
{
//textFile.MoveToContent();
if(textFile.Name == "componentname")
{
dtc.Add(textFile.ReadString());
}
idValue = textFile.GetAttribute("id");
if (textFile.Name == "servinfo")
{
dtc.Add(idValue);
}
if (textFile.Name == "title")
{
dtc.Add(textFile.ReadString());
}
if (textFile.Name == "ptxt")
{
dtc.Add(textFile.ReadString());
}
}

dtc.ForEach(Console.WriteLine);

}

}

}
I am not sure what I can do in this situation?

Matt T Heffron 9-Oct-15 16:55pm

I think you might have been better off with the use of the inner reader from the reader.ReadSubtree() you had before, and then, like I pointed out, used the inner to process the contents of the system element with attribute value of "28". In general you'll need to look at the textFile.NodeType each time through the loop and figure out if you are at an Element, EndElement, etc. You might want to make a simple state-machine to help you process this and keep track of where you are in the nesting structure within each system element you are processing.
(Also, you should use the strongly typed List<string> class for dtc, not just List.)