access programmatically XML element change value, then put the xml string in a string variable

Question

Hi

I have one xml file which i would like to access programmatically and then access two elements change the values of it(BrandName, Manufacturer) and then put the resultant xml after the change to a string variable in c#

<?xml version="1.0" encoding="utf-8"?>
 
<Product ID="001" Name="Soap"> 
 
  <Price>10.00</Price> 
 
  <OtherDetails> 
 
    <BrandName>PlaceHolder1</BrandName> 
 
    <Manufacturer>PlaceHolder2</Manufacturer> 
 
  </OtherDetails> 
 
</Product>

Answer 1

Here is a sample you can use with .NET 3.5 or later:

            XDocument doc = XDocument.Load("input.xml");
            doc.Root.Element("OtherDetails").SetElementValue("BrandName", "foo");
            doc.Root.Element("OtherDetails").SetElementValue("Manufacturer", "bar");
            string xml = doc.ToString();

Read more about LINQ to XML .

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MVP Data Platform Development My blog

Answer 2

Thanks for the reply

However i am getting object reference not set to an instance exception. if there is  amchange in the xml say

<?xml version="1.0" encoding="utf-8"?>
  <Order>
<Product ID="001" Name="Soap"> 
 
  <Price>10.00</Price> 
 
  <ns:OtherDetails xmlns:ns="http://abc.com/ab"> 
 
    <BrandName>PlaceHolder1</BrandName> 
 
    <Manufacturer>PlaceHolder2</Manufacturer> 
 
  </OtherDetails> 
 
</Product>

</Order>

Answer 3

I suggest you start reading the LINQ to XML documentation I pointed you to in my earlier answer.  As for your latest XML sample (assuming it is well-formed after changing </OtherDetails> into </ns:OtherDetails>), it has an element in a namespace so you need to adapt the code to

            XDocument doc = XDocument.Load("input.xml");
            XNamespace ns = "http://abc.com/ab";
            XElement details = doc.Root.Element("Product").Element(ns + "OtherDetails");
            details.SetElementValue("BrandName", "foo");
            details.SetElementValue("Manufacturer", "bar");
            string xml = doc.ToString();

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MVP Data Platform Development My blog

Answer 4

i am getting object reference not set to an instance exception.

and i get it on

Element(ns + "OtherDetails");

Answer 5

i am getting object reference not set to an instance exception.

and i get it on

Element(ns + "OtherDetails");

Well the posted sample was not even well-formed, after correcting it to

<?xml version="1.0" encoding="utf-8"?>
<Order>
  <Product ID="001" Name="Soap">

    <Price>10.00</Price>

    <ns:OtherDetails xmlns:ns="http://abc.com/ab">

      <BrandName>PlaceHolder1</BrandName>

      <Manufacturer>PlaceHolder2</Manufacturer>

      </ns:OtherDetails>

    </Product>

</Order>

I tested the code

            XDocument doc = XDocument.Load("input.xml");
            XNamespace ns = "http://abc.com/ab";
            XElement details = doc.Root.Element("Product").Element(ns + "OtherDetails");
            details.SetElementValue("BrandName", "foo");
            details.SetElementValue("Manufacturer", "bar");
            string xml = doc.ToString();
            Console.WriteLine(xml);

it compiles and runs fine for me, outputting

<Order>
  <Product ID="001" Name="Soap">
    <Price>10.00</Price>
    <ns:OtherDetails xmlns:ns="http://abc.com/ab">
      <BrandName>foo</BrandName>
      <Manufacturer>bar</Manufacturer>
    </ns:OtherDetails>
  </Product>
</Order>

I will repeat my suggestion to start reading and working through LINQ to XML , if you then still have problems you will need to show us minimal but complete enough samples allowing us to reproduce the error.

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MVP Data Platform Development My blog