how to read, update, delete data from and to xml file with C#

There are various ways to achieve the same.

If you want to keep reading sequentially, you can use XmlReader.

If you want to read/update/delete/insert at particular location, you can use two approaches
1. XmlDocument and XPath.
2. LinQ to XML

For XmlDocument approach, First you declare variable and load xml.

XmlDocument xDoc = new XmlDocument();
xDoc.Load("YourFile.Xml");

Then, you read like

string nodeValue = xDoc .DocumentElement.SelectSingleNode("NodeName").InnerText;

You can update value like

xDoc.DocumentElement.SelectSingleNode("NodeName").InnerText = newValue;

Note, that in above code, "NodeName is actually Xpath. You can give it like Node/ChildNode/GrandChildNode and so on. You can find more details about xPath at http://www.w3schools.com/xpath/default.asp[^]

Hope that helps. If it does mark it as answer/upvote.

Thanks
Milind