ws vs wcf

webservices uses XmlSerializer. A Web Service is programmable application logic accessible via standard Web protocols(Simple Object Access Protocol), which uses standards based technologies (XML for data description and HTTP for transport) to encode and transmit application data. consumers only need to understand how to send and receive SOAP messages (HTTP and XML). webservice can be hosted in iis and outside of iis. In Web service System.XML.Serialization is supported while in the WCF Service System.RunTime.Serialization is supported

wcf uses DataContractSerializer. Windows Communication Foundation (WCF) is a framework for building service-oriented applications. for secure applications, chat service that allows two people to communicate, to poll a service for the latest data feeds we use wcf. WCF is a replacement for all earlier web service technologies from Microsoft. An endpoint in WCF can be communicated with just as easily over SOAP/XML,TCP/binary,as this reduces the amount of new code needed.
WCF is flexible because its services can be hosted in different types of applications (IIS,WAS, Self-hosting, Managed Windows Service)

limits of xmlserializer:
----------------------
1.Only the public fields and properties of .NET Framework objects are translated into XML.
2.Hashtable cannot be serialized into XML.
3.Web Services can be accessed only over HTTP & it works in stateless environment

xml read, write, modify data in asp.net

wsex.aspx.cs:
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Xml;

public partial class wsex : System.Web.UI.Page
{
string xmlfile = @"C:\vision\first\emp.xml";
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
getdata();
}
void getdata()
{
wsxml ws = new wsxml();
GridView1.DataSource = ws.getdata();
GridView1.DataBind();
}

protected void Button1_Click(object sender, EventArgs e)//insert
{
XmlDocument xd = new XmlDocument();
xd.Load(xmlfile);
XmlElement xe = xd.CreateElement("emp");

XmlElement id = xd.CreateElement("id");
id.InnerText = TextBox1.Text;
xe.AppendChild(id);

XmlElement nam = xd.CreateElement("name");
nam.InnerText = TextBox2.Text;
xe.AppendChild(nam);

XmlElement ad = xd.CreateElement("add");
ad.InnerText = TextBox3.Text;
xe.AppendChild(ad);

xd.DocumentElement.AppendChild(xe);
xd.Save(xmlfile);
Response.Redirect("~/wsex.aspx");

}
protected void Button2_Click(object sender, EventArgs e)//update
{
DataSet ds = new DataSet();
ds.ReadXml(Server.MapPath("emp.xml"));
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
{
if (TextBox1.Text == ds.Tables[0].Rows[i]["id"].ToString())
{
ds.Tables[0].Rows[i]["name"] = TextBox2.Text;
ds.Tables[0].Rows[i]["add"] = TextBox3.Text;
ds.WriteXml(Server.MapPath("emp.xml"));
}
}
Response.Redirect("~/wsex.aspx");
}
protected void Button3_Click(object sender, EventArgs e)//delete
{
DataSet ds = new DataSet();
ds.ReadXml(Server.MapPath("emp.xml"));
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
{
if (TextBox1.Text == ds.Tables[0].Rows[i]["id"].ToString())
{
ds.Tables[0].Rows[i].Delete();
ds.WriteXml(Server.MapPath("emp.xml"));
}
}
Response.Redirect("~/wsex.aspx");
}
}

emp.xml:

<?xml version="1.0" standalone="yes"?>

<employee>

  <emp>

    <id>1</id>

    <name>s</name>

    <add>s</add>

  </emp>

  <emp>

    <id>2</id>

    <name>b</name>

    <add>che</add>

  </emp>

  <emp>

    <id>3</id>

    <name>c</name>

    <add>ban</add>

  </emp>

</employee>

wsxml:(webservice class)

[WebMethod]

    public DataSet getdata()

    {

        DataSet ds = new DataSet();

        ds.ReadXml(Server.MapPath("emp.xml"));

        return ds;

    }