Introduction:
Here I am creating a web service for a login check and consuming it in a web 
application. Follow the given steps to do it. 
Step1: Create a web service using the following steps.
- Go to Visual Studeo 2010  and take a New Project.
- 
	Select .NET Framework 3.5.
- 
	Take a ASP.NET Web Service Application.
- 
	Give it a name and click ok button.
Step 2: Write the following code on the .asmx.cs page.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Data.SqlClient;
using System.Data;
namespace loginwebservice
{
    /// 
<summary>
    /// Summary 
description for Service1
    /// 
</summary>
    [WebService(Namespace =
"http://tempuri.org/")]
    [WebServiceBinding(ConformsTo =
WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from 
script, using ASP.NET AJAX, uncomment the following line. 
    // [System.Web.Script.Services.ScriptService]
    public class
Service1 : System.Web.Services.WebService
    {
        [WebMethod]
        public 
DataSet login(string uname,
string pwd)
        {
            SqlDataAdapter da =
new SqlDataAdapter("select 
* from login where user_name ='" + uname + "' 
and password='" + pwd + "' ",
       
            
@"DataSource=SERVER_NAME;Initial Catalog=EMP;Integrated 
Security=True");
            DataSet 
ds = new DataSet();
            da.Fill(ds);
            return ds;
        }
    }
}
 
Step 3: Run this application. 
Output:
 
 ![login check through web service]() 
Step 4:  Now create a web application to consume the service. For doing 
this, follow the given steps.
- Go to Visual Studeo 2010  and take a New Project.
- 
	Select a ASP.NET Empty Web Application.
- Give it a name and click ok button.
 
Step 5: Now add service in your web 
application. Go to Solution Explorer and right click at your project. Click at 
Add Web Reference. A new window will open. Its screen-shot is given below.
 
![login check through web service]()
- Now paste the URL of your service and 
	click at Go button.
- Click on Add reference. Now service has 
	added into your project.
- Now go to design page of your web 
	application and take some user interfaces to accept user name and password 
	and a button.
- Write the following code in the .aspx.cs 
	file on buton Click event.
 
 protected
	void btnok_Click(object 
	sender, EventArgs e)
 {
 localhost.Service1 obj=new 
	localhost.Service1();
 DataSet ds = 
	obj.login(TextBox1.Text, TextBox2.Text);
 if (ds.Tables[0].Rows.Count > 0)
 {
 Label1.Text = "Hi ," + 
	ds.Tables[0].Rows[0][1].ToString();
 }
 else
 {
 Label1.Text = "Invalid UserName 
	or Password.";
 }
 }
 
Step 6: Run the web application.
Output:
![login check through web service]()
Write the user name and password in TextBoxes and click the ok Button. In 
this example, Database name is EMP which has a table Login. There is only one 
record in Login table - abc is user_name and xyz is password. Do right input for 
user name and password and click the ok button. 
Output: 
 ![login check through web service]()
Now do wrong input for user name and password 
and click the ok button. 
Output:      
 
![login check through web service]()