c# - Subtracting from an XML file -

i have xml file contains stock of tyres nodes this

<stock>   <tyre>     <manufacturer>yokohama</manufacturer>     <quantity>500</quantity>   </tyre> </stock> 

on form have order form can select manufacturer of tyre in textbox or combobox drop down, , enter amount in textbox , subtract , update quantity node.

would have each loop , through each tyre manufacturer node name entered textbox?

foreach (xmlnode xnode in xdoc.selectnodes("stock/tyre")) {     stock st = new stock();     st.manufacturer = xnode.selectsinglenode("manufacturer ").innertext;     //??? } 

where comment ? stuck how subtract value in textbox stock quantity in xml file.

should doing way or wrong?

this can done more , elegant using linq xml:

var filename = @"c:\test.xml"; var manufacturer = "yokohama"; var amount = 100;  var doc = xdocument.load(filename); var node = doc.xpathselectelements("stock/tyre/manufacturer")               .firstordefault(x => x.value == manufacturer); if (node != null) {     var valuenode = node.parent.xpathselectelement("quantity");     if (valuenode != null)         valuenode.setvalue(convert.toint32(valuenode.value)  - amount); }  doc.save(filename);