How to update XML doc

Question

1.00/5 (1 vote)

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Hi all,

I am working on xml.

successfully save my xml document when I update this not working.
my code is

if (!File.Exists(path))
            {
                //save
                XElement xml = new XElement("Formulas",
                                new XElement("Formula", txtFormula.Text));
                xml.Save(path);
            }
            else
            {
                //update
                XDocument doc = XDocument.Load(path);
                var xmlupdate = doc.Descendants().Elements("Formulas").Where(f => f.Element("Formula").Value == txtFormula.Text).FirstOrDefault();
                doc.Save(path);


            }

where I went wrong.

Posted 2-Apr-13 19:10pm

U@007

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Comments

Sergey Alexandrovich Kryukov 3-Apr-13 1:19am

"Not working" is not informative.
—SA

U@007 3-Apr-13 1:40am

when update return null value.So, how to update this

2 solutions

Solution 2

Sorry I don't speak C but I think you may be having an issue with using the XDocument. It is far easier to work with XElement until you get some practice with XDocument. Try [this] for starters. See the section on using XElement without using XDocument.

Posted 2-Apr-13 20:07pm

Jim Meadors

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vijay__p · Accepted Answer · 2013-04-02T19:30:00

Solution 1

Hi,

You performed update in conditional statement.

Try below code

C#

if (!File.Exists(path))
            {
                //save
                XElement xml = new XElement("Formulas",
                                new XElement("Formula", txtFormula.Text));
                xml.Save(path);
            }
            else
            {
                //update
                XDocument doc = XDocument.Load(path);
                var xmlupdate = doc.Descendants("Formulas")
                    .FirstOrDefault().Element("Formula").Value = txtFormula.Text;
                doc.Save(path);
            }

Posted 2-Apr-13 19:30pm

vijay__p

Comments

U@007 3-Apr-13 1:38am

it's not working patel

vijay__p 3-Apr-13 1:43am

Dear i have tested this code in sample application and it worked!
Just use one codition for .FirstOrDefault();
if it is null then do not perform any operation as no element exists.

Try below code. it is from sample application

var path = @"C:\Temp\test.xml";
if (!File.Exists(path))
{
//save
XElement xml = new XElement("Formulas",
new XElement("Formula", DateTime.Now.ToString()));
xml.Save(path);
}
else
{
//update
XDocument doc = XDocument.Load(path);
var xmlupdate = doc.Descendants("Formulas")
.FirstOrDefault().Element("Formula").Value = "formula_" + DateTime.Now.ToString();
doc.Save(path);
}

U@007 3-Apr-13 1:59am

ya it's working fine. actually I written the dobule equals insted of single equals. now fine.
Thank you

:) 5+.