Adding XElement to XML file using Linq to XML

Adding XElement to XML file using Linq to XML

Using Linq to XML, I am trying to add an XElement to an existing XML file. It has to be done in the Windows Phone .NET framework. Currently my XML file looks like this:

    <?xml version="1.0" encoding="utf-8"?>     <Kids>       <Child>         <Name>Kid1</Name>         <FirstName>hisname</FirstName>       </Child>     </Kids>  and my code looks like this:        using (IsolatedStorageFileStream stream =                 new IsolatedStorageFileStream("YourKids.xml", fileMode, store))     {          XDocument x = XDocument.Load(stream);         XElement t =  new XElement("Child",                                            new XElement("Name", pName),                                            new XElement("FirstName", pFirstname));         t.Add(from el in x.Elements()              where el == el.Descendants("Child").Last()              select el);         x.Save(stream);     }  this doesn't do what I want to achieve. I want to add a new "Child" element to the the exisiting XML file like this :       <?xml version="1.0" encoding="utf-8"?>     <Kids>       <Child>         <Name>Kid1</Name>         <FirstName>hisname</FirstName>       </Child>     <Child>         <Name>kid2</Name>         <FirstName>SomeName</FirstName>       </Child>     </Kids>  Could use some help because I am stuck ;-)  After the tips from GSerjo, my code looks like this now:   try             {                  if (store.FileExists("YourKids.xml"))                 {                        using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream("YourKids.xml",FileMode.Open, store))                     {                           var x = XElement.Load(stream);                         var t =  new XElement("Child",                                                         new XElement("Name", pName),                                                         new XElement("FirstName", pFirstname)                                                                   );                          x.Add(t);                          x.Save(stream);                             stream.Close();                         return;                     }                  }                 else                 {                        using (IsolatedStorageFileStream CreateIsf = new IsolatedStorageFileStream("YourKids.xml",FileMode.Create,store))                     {                          var xDoc = new XElement("Kids",                                                      new XElement("Child",                                                        new XElement("Name", pName),                                                        new XElement("FirstName", pFirstname)                                                                  )                                                    );                          xDoc.Save(CreateIsf);                         CreateIsf.Close();                          return;                     }                 }             }             catch (Exception ex)             {               message = ex.Message;             } 

Which gives me an xml file like this:

<?xml version="1.0" encoding="utf-8"?> <Kids>   <Child>     <Name>test</Name>     <FirstName>test</FirstName>   </Child> </Kids><?xml version="1.0" encoding="utf-8"?> <Kids>   <Child>     <Name>test</Name>     <FirstName>test</FirstName>   </Child>   <Child>     <Name>testing</Name>     <FirstName>testing</FirstName>   </Child> </Kids> 

Which is still not correct, any ideas anyone ?

Answers & Comments...

Answer: 1

Initial xml file

<?xml version="1.0" encoding="utf-8"?> <Kids>   <Child>     <Name>Kid1</Name>     <FirstName>hisname</FirstName>   </Child> </Kids> 

Following code add one new child to existing xml

    [Test]     public void Test()     {         string filPath = @"YourKids.xml";         var root = XElement.Load(filPath);          var newChild =  new XElement("Child",                                    new XElement("Name", "NewName"),                                    new XElement("FirstName", "NewFirstName"));          root.Add(newChild);         root.Save(filPath);     } 

Result xml file

<?xml version="1.0" encoding="utf-8"?> <Kids>   <Child>     <Name>Kid1</Name>     <FirstName>hisname</FirstName>   </Child>   <Child>     <Name>NewName</Name>     <FirstName>NewFirstName</FirstName>   </Child> </Kids> 

Update

Bug on save, you should set stream length to 0

Explanation

After reader existing file, stream does not remove any data

using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream("YourKids.xml",FileMode.Open, store))                     {                         var x = XElement.Load(stream); 

So when you call, data has been appended

   x.Save(stream);    stream.Close(); 

Add stream.SetLength(0); before x.Save(stream); and all data will be overwritten.

Here is full version

            if (store.FileExists("YourKids.xml"))             {                 using (var stream = new IsolatedStorageFileStream("YourKids.xml", FileMode.Open,                                                                                      store))                 {                     var x = XElement.Load(stream);                     var t = new XElement("Child",                                          new XElement("Name", pName),                                          new XElement("FirstName", pFirstname)                         );                     x.Add(t);                     stream.SetLength(0);                     x.Save(stream);                     stream.Close();                 }             }             else             {                 using (var CreateIsf = new IsolatedStorageFileStream("YourKids.xml", FileMode.Create, store))                 {                     var xDoc = new XElement("Kids",                                             new XElement("Child",                                                          new XElement("Name", pName),                                                          new XElement("FirstName", pFirstname)                                                 )                         );                     xDoc.Save(CreateIsf);                     CreateIsf.Close();                 }             } 

Please note: I've removed return statements as useless.

P.S. Take a look on resharper, it can improve code.

Answer by GSerjo for Adding XElement to XML file using Linq to XML

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