Csharp/CSharp Tutorial/XML LINQ/Query

Query XML: All descendants in document

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResult = from c in customers.Descendants() select c.Name;
            foreach (var item in queryResult)
            {
                Console.WriteLine(item);
            }
        }
    }

Query XML: All distinct descendants in document

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResult = from c in customers.Descendants() select c.Name;
            foreach (var item in queryResult.Distinct())
            {
                Console.WriteLine(item);
            }
        }
    }

Query XML: Attributes named "Company"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResult =
                from c in customers.Descendants("customer").Attributes("Company")
                select c.Name;
            foreach (var item in queryResult)
            {
                Console.WriteLine(item);
            }
        }
    }

Query XML: attributes named "orderYear"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResults =
                from c in customers.Descendants("order").Attributes("orderYear")
                select c;
            foreach (var item in queryResults)
            {
                Console.WriteLine(item);
            }                
        }
    }

Query XML: Attributes of descendants named "customer"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResult = from c in customers.Descendants("customer").Attributes() select c.Name;
            foreach (var item in queryResult)
            {
                Console.WriteLine(item);
            }
        }
    }

Query XML by select an element

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResult = from c in customers.Elements() select c.Name;
            foreach (var item in queryResult)
            {
                Console.WriteLine(item);
            }
        }
    }

Query XML: Descendants named "customer"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResult = from c in customers.Descendants("customer")  select c.Name;
            foreach (var item in queryResult)
            {
                Console.WriteLine(item);
            }
        }
    }

Query XML: Earliest year in which orders were placed

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResults =
                from c in customers.Descendants("order").Attributes("orderYear")
                select c.Value;                      
            Console.WriteLine("Earliest year in which orders were placed: {0}", queryResults.Min());
           
        }
    }

Query XML: Values of customer attributes named "Company"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResults =
                from c in customers.Descendants("customer").Attributes("Company")
                select c;
            foreach (var item in queryResults)
            {
                Console.WriteLine(item);
            }
        }
    }

Query XML: Values of descendant attributes named "orderYear"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            string xmlFileName = "e.xml";
            XDocument customers = XDocument.Load(xmlFileName);
            var queryResults =
                from c in customers.Descendants("order").Attributes("orderYear")
                select c.Value;
            foreach (var item in queryResults)
            {
                Console.WriteLine(item);
            }              
        }
    }

Using Linq To query Xml

using System.Text;
using System.Xml.Linq;
using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Linq;
    class LinqToXml
    {
        static void Main()
        {
            XDocument doc = XDocument.Load("data.xml");
            var filtered = from p in doc.Descendants("Product")
                           join s in doc.Descendants("Supplier")
                           on (int)p.Attribute("SupplierID")
                               equals (int)s.Attribute("SupplierID")
                           where (decimal)p.Attribute("Price") > 10
                           orderby (string)s.Attribute("Name"),
                                   (string)p.Attribute("Name")
                           select new
                           {
                               SupplierName = (string)s.Attribute("Name"),
                               ProductName = (string)p.Attribute("Name")
                           };
            foreach (var v in filtered)
            {
                Console.WriteLine("Supplier={0}; Product={1}",
                                  v.SupplierName, v.ProductName);
            }
        }
    }
//File: data.xml
/*
<?xml version="1.0"?>
<Data>
  <Products>
    <Product Name="E" Price="9.99" SupplierID="1" />
    <Product Name="A" Price="14.99" SupplierID="2" />
    <Product Name="C" Price="13.99" SupplierID="1" />
    <Product Name="D" Price="10.99" SupplierID="3" />
  </Products>
</Data>
*/