Loop through sub XmlNodeList with C#

HI all,

I've searched for an answer to this, as I'm sure it will have been asked before, but can't find anything. It's quite a simple query..

I'm reading from a XML feed from a URL and can successfully loop through a node list for a top level node. However, within the Article node is a node called Categories, as an article can be associated with multiple categories. I then need to loop through this node list within each Article. In VB, I can do this as below, but I need to convert this to C# and can't find the equivalent

VB.NET:

Dim xtr As XmlTextReader = New XmlTextReader("http://feed.url.com")
        xtr.WhitespaceHandling = WhitespaceHandling.None
        Dim X As New XmlDocument
        X.Load(xtr)


      

        If Not X Is Nothing Then
            

            Try
                Dim ArticleList As XmlNodeList = X.SelectNodes("InfoStreamResults/Article")
                Dim Article As XmlNode


              

                For Each Article In ArticleList
                  



                    Dim CatNodesList As XmlNodeList = Article.SelectNodes("Categories/Category")
                    Dim category As XmlNode
                    For Each category In CatNodesList


                        ' do stuff, i.e.

			If Not Article.SelectSingleNode("nodename") Is Nothing Then
                        	nodename= safeEncode(Article.SelectSingleNode("nodename").Value)
                    	End If




                    Next


                Next


            Catch ex As Exception


              ' exception

            End Try
        End If

II can do the outer loop in C# fine, but when it comes to the equivalent of lines 17 to 28 as above, this DOESN'T work;

C#:

1    foreach (XmlNode category in Article.SelectNodes("Categories/Category"))
2    {
3       categoryID = category.SelectSingleNode("@ID").Value;
4       categoryName = EncodeIt(category.SelectSingleNode("category").InnerText);
5    }

So how do I loop through a set of sub nodes within a node using foreach as I do in VB.NET, but in C#?

Thanks, hope that makes sense.

Re: Loop through sub XmlNodeList with C#

Try the below code

if(X != null)

{

try

{

XmlNodeList ArticleList = X.SelectNodes("InfoStreamResults/Article");

foreach(XmlNode Article in ArticleList)

{

XmlNodeList CatNodesList = Article.SelectNodes("Categories/Category");

foreach( XmlNode category in CatNodesList)

{

//do stuff

if(Article.SelectSingleNode("nodename") != null)

{

nodename = safeEncode(Article.SelectSingleNode("nodename").Value);

}

catch

{

}

Re: Loop through sub XmlNodeList with C#

Thanks very much for the reply. I've tried your suggested code and it does seem to loop though now, so that's great. However, it doesn't write out the value for categoryName. My code now is:

XmlTextReader xtr = new XmlTextReader("http://url.feed.com"); 
    xtr.WhitespaceHandling = WhitespaceHandling.None;


    XmlDocument X = new XmlDocument();
    X.Load(xtr);


    if (!(X == null))
    {
        try
        {
            XmlNodeList ArticleList = X.SelectNodes("InfoStreamResults/Article");
            foreach(XmlNode Article in ArticleList)
            {
                

                try
                {
                    XmlNodeList CatNodesList = Article.SelectNodes("Categories/Category");
                    foreach( XmlNode category in CatNodesList)
                    {
                      

                        if (Article.SelectSingleNode("Category") != null)
                        {
                            categoryName = EncodeIt(Article.SelectSingleNode("Category").Value);
                            Response.Write(categoryName);
                            Response.Write("<br />");
                        }


                    }


                }
                catch (Exception ex)
                {
                    Response.Write(ex);
                    Response.Write("<br />");


                }
  



            }
        }
        catch (Exception ex)
        {
            Response.Write(ex);
        }
    }

In the above, we don't enter the if statement on line 22. Is this the right way of referencing the node? I would have thought that now we are in another foreach loop, it would become category.SelectSingleNode("category"). But I tried that and that didn't work either.

Incidentally, a sample of my XML looks like this;

 
<InfoStreamResults Copyright="(c) 2006 xxxx." ArticleCount="1">
<Article Created="12:05:00" ID="1111">
  <Heading>heading title</Heading> 
  <Date>11/11/1111</Date> 
<Contents>
![CDATA[ blah blah ]]> 
  </Contents>

<Categories>
  <Category ID="11111">cat 1</Category>
<Category ID="11112">cat 2</Category>
  </Categories>
  </Article>

</InfoStreamResults>

You can see the Categories node as above and the two values inside it. How do you loop through each article, then loop through each set of Categories inside each Article, and get the value of each Category? Getting there - any more pointers much appreciated.

Re: Loop through sub XmlNodeList with C#

Thanks very much for the reply. I've tried your suggested code and it does seem to loop though now, so that's great. However, it doesn't write out the value for categoryName. My code now is:

XmlTextReader xtr = new XmlTextReader("http://url.feed.com"); 
    xtr.WhitespaceHandling = WhitespaceHandling.None;


    XmlDocument X = new XmlDocument();
    X.Load(xtr);


    if (!(X == null))
    {
        try
        {
            XmlNodeList ArticleList = X.SelectNodes("InfoStreamResults/Article");
            foreach(XmlNode Article in ArticleList)
            {
                

                try
                {
                    XmlNodeList CatNodesList = Article.SelectNodes("Categories/Category");
                    foreach( XmlNode category in CatNodesList)
                    {
                      

                        if (Article.SelectSingleNode("Category") != null)
                        {
                            categoryName = EncodeIt(Article.SelectSingleNode("Category").Value);
                            Response.Write(categoryName);
                            Response.Write("<br />");
                        }


                    }


                }
                catch (Exception ex)
                {
                    Response.Write(ex);
                    Response.Write("<br />");


                }
  



            }
        }
        catch (Exception ex)
        {
            Response.Write(ex);
        }
    }

Incidentally, a sample of my XML looks like this;

 
<InfoStreamResults Copyright="(c) 2006 xxxx." ArticleCount="1">
<Article Created="12:05:00" ID="1111">
  <Heading>heading title</Heading> 
  <Date>11/11/1111</Date> 
<Contents>
![CDATA[ blah blah ]]> 
  </Contents>

<Categories>
  <Category ID="11111">cat 1</Category>
<Category ID="11112">cat 2</Category>
  </Categories>
  </Article>

</InfoStreamResults>

Re: Loop through sub XmlNodeList with C#

Oops, double post, sorry.

Re: Loop through sub XmlNodeList with C#

Below is your code

        if (!(X == null))
        {
            try
           {
               XmlNodeList ArticleList = X.SelectNodes("InfoStreamResults/Article");
               foreach(XmlNode Article in ArticleList)
               {

                   try
                   {
                       XmlNodeList CatNodesList = Article.SelectNodes("Categories/Category");
                       foreach( XmlNode category in CatNodesList)
                       {

                           if (category != null)
                           {
                              string categoryName = category.InnerText;
                               Response.Write(categoryName);
                               Response.Write("<br />");
                           }

                       }

     }
                   catch (Exception ex)
                   {
                       Response.Write(ex);
                       Response.Write("<br />");

                   }


               }
           }
           catch (Exception ex)
           {
               Response.Write(ex);
           }
       }

-----

Mark it as answered if it helped you

Re: Loop through sub XmlNodeList with C#

Brilliant, thanks - that's worked.

Re: Loop through sub XmlNodeList with C#

Hi,

I am having a very similar problem, except it's slightly more complicated. I need to check the attribute value before deciding what to do with the inner text. I am converting a large xml file (100,000 lines) to a csv file, except i'm struggling with the custom attributes section - see below:

<product product-id="048002347">
    <display-name>Cotton crew-neck printed T-shirt</display-name>
    <long-description>Superdry cotton short-sleeved T-shirt with Osaka 6 print emblazoned across chest.</long-description>
    <online-flag>false</online-flag>
    <available-flag>true</available-flag>
    <searchable-flag>true</searchable-flag>
    <tax-class-id>default</tax-class-id>
    <brand>Superdry</brand>
    <manufacturer-name>Superdry</manufacturer-name>
    <custom-attributes>
      <custom-attribute attribute-id="Calendar Event">N/A</custom-attribute>
      <custom-attribute attribute-id="Care Instructions">Machine Wash 30°C</custom-attribute>
      <custom-attribute attribute-id="Colour">Black</custom-attribute>
      <custom-attribute attribute-id="Cuff Type">N/A</custom-attribute>
      <custom-attribute attribute-id="Exclusive">N/A</custom-attribute>
      <custom-attribute attribute-id="Fabric">Cotton</custom-attribute>
      <custom-attribute attribute-id="Fair Trade">N/A</custom-attribute>
      <custom-attribute attribute-id="Gender">Men</custom-attribute>
      <custom-attribute attribute-id="Guarantee">N/A</custom-attribute>
      <custom-attribute attribute-id="House of Fraser Magazine">No</custom-attribute>
      <custom-attribute attribute-id="Organic">No</custom-attribute>
      <custom-attribute attribute-id="Parent Colour">Black</custom-attribute>
      <custom-attribute attribute-id="Parent Style">TOPS</custom-attribute>
      <custom-attribute attribute-id="Range">PRE-SEASON/TRANSITIONAL</custom-attribute>
      <custom-attribute attribute-id="Recycled">N/A</custom-attribute>
      <custom-attribute attribute-id="Size">XL</custom-attribute>
      <custom-attribute attribute-id="Style">TOP- T-SHIRT</custom-attribute>
      <custom-attribute attribute-id="Television Line">No</custom-attribute>
      <custom-attribute attribute-id="Web Supply Lane">iForce Deliveries</custom-attribute>
      <custom-attribute attribute-id="qosListID">QOS1</custom-attribute>
      <custom-attribute attribute-id="sellByUnit">false</custom-attribute>
      <custom-attribute attribute-id="COMPOSITION">100% Cotton</custom-attribute>
    </custom-attributes>
  </product>

What I need to do is first check for the attribute-id value, i.e.

 XmlNodeList attributeList = n.SelectNodes("custom-attributes/custom-attribute");
string calendar = "null";
foreach (XmlNode a in attributeList)
{
   if (a.Attributes["attribute-id"].Value == "Calendar Event") 
   { 
       calendar = a.InnerText; 
   }              
}

And then assign it the inner value if it exists, else leave the string as null. Now all that's happening is the string is returned as nul every single time.

I am using a textwriter to write the data to a textfile, so a shortened version of the code (with everything required for this purpose is below)

 int id = 0;

            string CSVFile = "HOFProds.txt";
            TextWriter tw = new StreamWriter(CSVFile);
            tw.WriteLine("id|product-id|ean|display-name|long-description|online-flag|available-flag|" +
                "searchable-flag|tax-class-id|brand|manufacturer-name|Calendar Event|Care Instructions|Colour|" +
                "Cuff Type|Exclusive|Fabric|Fair Trade|Gender|Guarantee|House of Fraser Magazine|Organic|Parent Colour|" +
                "Parent Style|Range|Recycled|Size|Style|Television Line|Web Supply Lane|qosListID|sellByUnit|COMPOSITION|" +
                "PrimaryImage|SecondaryImage1|SecondaryImage2|Sizing|Finish|Material|Skin Type|Animal Tested|" +
                "WEIGHT|UnitMeasure|UnitQty|UnitQtyPrd|SecondaryImage3|SecondaryImage4|SecondaryImage5");

            XmlDocument hofProds = new XmlDocument();
            hofProds.Load("StagingHofCatalog.xml");

            XmlNodeList productList = null;
            productList = hofProds.GetElementsByTagName("product");

            foreach (XmlNode n in productList)
            {
                id = id + 1;
                string ean = "null";
                string displayName = "null";
                string longDescription = "null";
                string onlineFlag = "null";
                string availableFlag = "null";
                string searchableFlag = "null";
                string taxClass = "null";
                string brand = "null";
                string manufacturerName = "null";

                if (n["ean"] != null) { ean = n["ean"].InnerText; }

                if (n["display-name"] != null) { displayName = n["display-name"].InnerText; }

                if (n["long-description"] != null) { longDescription = n["long-description"].InnerText; }

                if (n["online-flag"] != null) { onlineFlag = n["online-flag"].InnerText; }

                if (n["available-flag"] != null) { availableFlag = n["available-flag"].InnerText; }

                if (n["searchable-flag"] != null) { searchableFlag = n["searchable-flag"].InnerText; }

                if (n["tax-class-id"] != null) { taxClass = n["tax-class-id"].InnerText; }

                if (n["brand"] != null) { brand = n["brand"].InnerText; }

                if (n["manufacturer-name"] != null) { manufacturerName = n["manufacturer-name"].InnerText; }

                string calendar = "null"; string care = "null"; string colour = "null"; string cuff = "null"; string exclusive = "null";
                string fabric = "null"; string fairtrade = "null"; string gender = "null"; string guarantee = "null";
                string hofmagazine = "null"; string organic = "null";
                string parentColour = "null"; string parentStyle = "null"; string range = "null"; string recycled = "null";
                string size = "null"; string style = "null"; string tvLine = "null"; string webSupplyLane = "null"; string qosListID = "null";
                string sellByUnit = "null";
                string composition = "null"; string primaryImage = "null"; string SecondaryImage1 = "null"; string SecondaryImage2 = "null"; string Sizing = "null";
                string Finish = "null"; string Material = "null"; string SkinType = "null"; string AnimalTested = "null";
                string WEIGHT = "null"; string UnitMeasure = "null"; string UnitQty = "null"; string UnitQtyPrd = "null";
                string SecondaryImage3 = "null"; string SecondaryImage4 = "null"; string SecondaryImage5 = "null";

                XmlNodeList attributeList = n.SelectNodes("custom-attributes/custom-attribute");
                foreach (XmlNode a in attributeList)
                {
                    if (a.Attributes["attribute-id"].Value == "Calendar Event") { calendar = a.InnerText; }
                }

                tw.WriteLine(id + "|" + n.Attributes["product-id"].Value + "|" + ean + "|" + displayName + "|" +
                    longDescription + "|" + onlineFlag + "|" +
                    availableFlag + "|" + searchableFlag + "|" +
                    taxClass + "|" + brand + "|" +
                    manufacturerName + "|" + calendar + "|" + care + "|" + colour + "|" + cuff + "|" + exclusive + "|" + fabric + "|" +
                    fairtrade + "|" + gender + "|" + guarantee + "|" + hofmagazine + "|" + organic + "|" + parentColour + "|" +
                    parentStyle + "|" + range + "|" + recycled + "|" + size + "|" + style + "|" + tvLine + "|" +
                    webSupplyLane + "|" + qosListID + "|" + sellByUnit + "|" + composition + "|" +
                    primaryImage + "|" + SecondaryImage1 + "|" + SecondaryImage2 + "|" + Sizing + "|" +
                    Finish + "|" + Material + "|" + SkinType + "|" + AnimalTested + "|" + WEIGHT + "|" + UnitMeasure + "|" +
                    UnitQty + "|" + UnitQtyPrd + "|" + SecondaryImage3 + "|" + SecondaryImage4 + "|" + SecondaryImage5);
            }
            tw.Close();

Just to clarify that before we get to the custom-attributes section, the program works fine because the data is output correctly. It's only when I get to analyzing the custom-attributes section that does the data become construed.

I have tried to use a separate node list and insert the attributes that way except this doesn't have no binding or sequence then as sometimes the attributes may not exist, this is why i have to allow for them all and check them, if they are there then insert them, if not then insert null.

Hopefully I have been clear,

Many thanks for any help in advance,

ChanandCo

Re: Loop through sub XmlNodeList with C#

Haissam over a year ago you made this one.

I'm curious to know how would you accomplish same results using LINQ to XML?

-Anargeek77

Re: Loop through sub XmlNodeList with C#

Hey, you would need to convert your XMLDocument to an XDocument/Xelement to be able to use it with LINQ.

XElement elements = XElement.Load(pathToFile);


var ranges = from r in elements.DescendantsAndSelf("range")
            select r;


foreach (var x in ranges)
{
//do your work here.
}

HTH's :)

Re: Loop through sub XmlNodeList with C#

HI Hassam,

You wrote the code above to get the category.innerxml out but what if I wanted to get the text and the Id number out. for example

<Category ID="430009730">International affairs</Category>

how would i get the id as well as the international affairs out.

Please help or anyone please help

Thanks,

R8VI

Re: Loop through sub XmlNodeList with C#

You can select the attribute.

Please see the following example:-

http://www.csharp-examples.net/xml-nodes-by-attribute-value/

Re: Loop through sub XmlNodeList with C#

Your solution worked for me

Cheers,

Sudha