C# Create, read, write XML files

<?xml version="1.0" encoding="utf-8"?> 
<Advertisements> 
 <Ad> 
 <ImageUrl></ImageUrl> 
 <NavigateUrl></NavigateUrl> 
 <Impressions>10</Impressions> 
 <Keyword>gucas01</Keyword> 
 </Ad> 
 <Ad> 
 <ImageUrl></ImageUrl> 
 <NavigateUrl></NavigateUrl> 
 <Impressions>20</Impressions> 
 <Keyword>gucas02</Keyword> 
 </Ad> 
 <Ad> 
 <ImageUrl></ImageUrl> 
 <NavigateUrl></NavigateUrl> 
 <Impressions>30</Impressions> 
 <Keyword>gucas03</Keyword> 
 </Ad> 
 <Ad> 
 <ImageUrl></ImageUrl> 
 <NavigateUrl></NavigateUrl> 
 <Impressions>40</Impressions> 
 <Keyword>gucas04</Keyword> 
 </Ad> 
 <Ad> 
 <ImageUrl></ImageUrl> 
 <NavigateUrl></NavigateUrl> 
 <Impressions>50</Impressions> 
 <Keyword>gucas05</Keyword> 
 </Ad> 
 <Ad> 
 <ImageUrl></ImageUrl> 
 <NavigateUrl></NavigateUrl> 
 <Impressions>30</Impressions> 
 <Keyword>google</Keyword> 
 </Ad> 
</Advertisements> 

/// <summary> 
 /// Create XML file /// </summary> 
 /// <param name="filename"></param> 
 public void CreateXmlFile(string filename) 
 { 
  XmlDocument xmldoc = new XmlDocument(); 
  XmlNode node; 
  node = ("1.0", "utf-8", null); 
  (node); 
  XmlNode root = ("Users"); 
  (root); 
  CreateNode(xmldoc, root, "UserName", "zhengyd"); 
  CreateNode(xmldoc, root, "Email", "zhengyd@,cn"); 
  CreateNode(xmldoc, root, "Url", ",cn"); 
  CreateNode(xmldoc, root, "Age", "27"); 
  try 
  { 
   ((filename)); 
   ("Creating XML file successfully!"); 
  } 
  catch (Exception ex) 
  { 
   (); 
  } 
 } 
 /// <summary> 
 /// Write to XML file /// </summary> 
 /// <param name="file"></param> 
 public void WriteXmlFile(string file) 
 { 
  XmlDocument xmdoc = new XmlDocument(); 
  try 
  { 
   ((file)); 
   XmlNode root = ("Advertisements"); 
   if (root != null) 
   { 
    XmlNode node = (, "Ad", null); 
    CreateNode(xmdoc, node, "ImageUrl", ""); 
    CreateNode(xmdoc, node, "NavigateUrl", ""); 
    CreateNode(xmdoc, node, "Impressions", "30"); 
    CreateNode(xmdoc, node, "Keyword", "google"); 
    (node); 
   } 
   ((file)); 
   ("Writing to XML file successfully.<br>"); 
  } 
  catch(Exception ex) { 
   (); 
  } 
 } 
 /// &lt;summary&gt; 
 /// Create node /// &lt;/summary&gt; 
 /// &lt;param name="xmldoc"&gt;&lt;/param&gt; 
 /// &lt;param name="parentnode"&gt;&lt;/param&gt; 
 /// &lt;param name="name"&gt;&lt;/param&gt; 
 /// &lt;param name="value"&gt;&lt;/param&gt; 
 public void CreateNode(XmlDocument xmldoc, XmlNode parentnode, string name, string value) 
 { 
  XmlNode node = (, name, null); 
   = value; 
  (node); 
 } 
 /// &lt;summary&gt; 
 /// Read XML file /// &lt;/summary&gt; 
 /// &lt;param name="file"&gt;&lt;/param&gt; 
 private void ReadFile(string file) 
 { 
  XmlDocument xmldoc = new XmlDocument(); 
  try 
  { 
   ((file)); 
   XmlNode node = ("Advertisements"); 
   if (node != null) 
   { 
    TreeNode root = new TreeNode(); 
     = ; 
    (root); 
    foreach (XmlNode xnode in ("Advertisements/Ad")) 
    { 
     TreeNode tnode = new TreeNode(); 
      = ("&lt;" +  + "&gt;"); 
     (tnode); 
      foreach (XmlNode xcnode in ) 
      { 
       TreeNode tcnode = new TreeNode(); 
        = ("&lt;" +  + "&gt;" +  + "&lt;/" +  + "&gt;"); 
       (tcnode); 
      } 
     TreeNode ttnode = new TreeNode(); 
      = ("&lt;/" +  + ""); 
     (ttnode); 
    } 
    TreeNode tpnode = new TreeNode(); 
     = ("&lt;/" +  + "&gt;"); 
    (tpnode); 
   } 
  } 
  catch (Exception ex) 
  { 
   (); 
  } 
 }