Adding nodes to an existing xml file

[Daljeet Hanspal]

hi ....
i am trying to add a new node to an existing xml file in c# ..........
the code is as follows:

XmlDocument doc = new XmlDocument();
string filename = @"C:\Documents and Settings\Administrator\My Documents\Visual Studio 2005\Projects\xml\xml\bin\Debug\bookstore.xml";
//create a new node
XmlElement newbook = doc.CreateElement("book");

//set attribute
newbook.SetAttribute(label1.Text, textBox1.Text);

//create new element
XmlElement npublication = doc.CreateElement(label2.Text);
npublication.InnerText = textBox2.Text;
newbook.AppendChild(npublication);

XmlElement nisbn = doc.CreateElement(label3.Text);
nisbn.InnerText = textBox3.Text;
newbook.AppendChild(nisbn);

XmlElement ntitle = doc.CreateElement(label4.Text);
ntitle.InnerText = textBox4.Text;
newbook.AppendChild(ntitle);

XmlElement nname = doc.CreateElement(groupBox2.Text);
newbook.AppendChild(nname);

XmlElement fname = doc.CreateElement(label5.Text);
fname.InnerText = textBox5.Text;
nname.AppendChild(fname);

XmlElement lname = doc.CreateElement(label6.Text);
lname.InnerText = textBox6.Text;
nname.AppendChild(lname);

XmlElement nprice = doc.CreateElement(label7.Text);
nprice.InnerText = textBox7.Text;
newbook.AppendChild(nprice);

XmlNode xn = doc.DocumentElement;
xn.AppendChild(newbook);


i get this message "Object reference not set to an instance of an object."

please help me out

[pronerd]

It sounds like your problem is with your language syntax, not XML. You should probably post your question in a form that supports what ever language you are using.

Also you may want to google and review basic forum guidelines. Posts like these generally will not get much of a response. More specific information is needed. For instance when do you get that error? When compiling, at run time? It also looks like the code is incomplete. There are a number of objects that are not defined in the same provided, and there are other objects like filename that never seem to be used.

[jkmyoung]

Could we see where you are declaring each of the labels, textboxes, etc??

This really seems like something that should be caught in the compiler with a warning.