// Create a new object that relates to your .master file control and call the FindControl function to return its properties
Xml xMasterHeaderXML = (Xml)Master.FindControl("xmlHeader");
 
// Do a basic is null check to see if hte control is there or not
if (xMasterHeaderXML != null)
{
     // Set whatever properties and values you need.
     xMasterHeaderXML.DocumentContent = "<root></root>";
     xMasterHeaderXML.TransformSource = "xsl/header.xsl";
}
 

 
XmlDocument xdocLocalFile = new XmlDocument();
 
xdocLocalFile.Load("MyXmlFile.xml");
 
foreach (XmlNode xNodeCopy in
          xdocLocalFile.SelectNodes("/root/phunk"))
{
     XmlNode xNodeNew =
     xdocLocalFile.CreateNode(XmlNodeType.Element, "NewNodeName", null);
 
     xNodeNew.InnerText =
     xNodeCopy.SelectSingleNode("CurrentNodeName").FirstChild.Value;
 
     xNodeCopy.InsertAfter(xNodeNew, xNodeCopy.LastChild);
}
 

 
XmlDocument xdocLocalFile = new XmlDocument();
 
xdocLocalFile.Load("MyXmlFile.xml");
 
foreach (XmlNode xNodeReplace in
           xdocLocalFile.SelectNodes("root/phunk"))
{
           xNodeReplace.FirstChild.InnerText = "My new Value";
}
 

 
XmlDocument xdocLocalFile = new XmlDocument();
 
xdocLocalFile.Load("MyXmlFile.xml");
 
foreach (XmlNode xNodeReplace in
     xdocLocalFile.SelectNodes("root/phunk/firstname"))
{
     xNodeReplace.ParentNode.ParentNode.RemoveChild(xNodeReplace.ParentNode);
}
 

 
XmlDocument xdocLocalFile = new XmlDocument();
 
xdocLocalFile.Load("MyXmlFile.xml");
 
foreach (XmlNode xNodeReplace in
          xdocLocalFile.SelectNodes("root/phunk"))
{
	XmlNode xNodeNew =
        xdocLocalFile.CreateNode(XmlNodeType.Element, "NewColumnName", null);
	xNodeNew.InnerText = "Here is my new value";
 
	xNodeReplace.InsertAfter(xNodeNew, xNodeReplace.LastChild);
}
 

 
HtmlMeta hmRobots = new HtmlMeta();
 
// Get a reference to the page header element.
HtmlHead hhRobots = (HtmlHead)Page.Header;
 
// Define an HTML <meta> element that is useful for search engines.
hmRobots.Name = "robots";
hmRobots.Content = "noindex,noarchive,follow";
hhRobots.Controls.Add(hmRobots);
 

To create a cookie on your site...

 
// Lets check if it exists or not yet.
if (Request.Cookies["MySite_LastVisit"] == null)
{
 
// Create new Cookie object to store users last visit to the site.
HttpCookie ckUserLastVisit = new HttpCookie("MySite_LastVisit");
 
// Get current date/time
DateTime dtNow = DateTime.Now;
 
// Set the cookie value.
ckUserLastVisit.Value = dtNow.ToString();
 
// Set the cookie expiration date. We will say one day from now
// but you could say as long as you want.
ckUserLastVisit.Expires = dtNow.AddDays(1);
 
// Add the cookie.
Response.Cookies.Add(ckUserLastVisit);
 
}

So that is it created. Lets see how to read that information back.

 
if (Request.Cookies["MySite_LastVisit"] == null)
{
// Just assign our value to a new string and then do what we want with it.
String sLastVisitDate = Request.Cookies["MySite_LastVisit"].Value;
}
 

That should be it, nice and simple.

private String fnGetImageSize(String sFilePath)
{
	try
	{
		System.IO.FileInfo fi = new System.IO.FileInfo(sFilePath);
		return ConvertBytesToMegabytes(fi.Length).ToString("0.00");
	}
	catch
	{
		return "0";
	}
}
 
static double ConvertBytesToMegabytes(long b)
{
	return (b / 1024f) / 1024f;
}

To install simply download the source, stick the Twitter.cs file in your bin directory and do the following on yoru page load. Then manipulate the returned XML as you wish in your XSL.

C# Code

 
Twitter twitNews = new Twitter();
XmlDocument xmlTwitterDoc =
twitNews.GetUserTimelineAsXML("username", "password", "johnboynolan",
Twitter.OutputFormatType.XML);
 

Simple as that!

Great if you are not in control of the data source such as twitter feeds.

 
<xsl:value-of select="concat(substring(text, 1, 100), '...')" />