Suppose that the user has to read the XML file he/she already generated. The application should provide functionality to extract all vendors from Canada, and after that the user has to process them in alphabetic order.
Web developer has to follow these steps:
1.Create the XDocument using the XML.
2.Navigate the XElement elements to reach the Vendor ones.
3.Take the XElement instances that have a child XElement whose name is Country and whose value is Canada.
The following VB.NET code lines illustrate how to perform filtering
Dim mydoc = XDocument.Load(path)
Dim canada = mydoc.Root.Elements(“Vendor”)
Where(Function(c) c.Element(“Country”).Value = “Canada”)
Select(Function(c)
New With {
.Name = c.Element(“Name”).Value,
.Country = c.Element(“Country”).Value
}
)
The Root property of the XDocument object represents the root node, and the Elements property gives access to the children of the root (Vendor). Web developer then filters them using a lambda expression. Note: The lambda expression code isn’t strongly typed because Web developer is working with XML, which is a loose-typed data format.
The next VB.NET code lines show how to sort Vendors by name, using the OrderBy method:
Dim sorted = mydoc.Root.Elements(“Vendor”)
OrderBy(Function(c) c.Element(“Name”).Value)
Select(Function(c) New With {
.Name = c.Element(“Name”).Value,
.Country = c.Element(“Country”).Value
})