To Check EmailId Already Exists In The DataBase Or Not

This is the Simple ASP.NET Program to check the Email id is already in the DataBase Or Not,If The Email id exists, Exists Message Will Be Displayed else Available Message Will Be Displayed,This Page Have 4 Web Controls they are as follows,

TextBox Id            =TextBox1
Button Id               =btCheck
Avaiable Label Id = lbAv //PageLoad Visible = false
Exists Label Id     =lbExists // PageLoad Visible = false



Code Behind

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

namespace EmailValidate
{
///

/// Summary description for WebForm1.
///

public class WebForm1 : System.Web.UI.Page
{
protected System.Web.UI.WebControls.TextBox TextBox1;
protected System.Web.UI.WebControls.Button btCheck;
protected System.Web.UI.WebControls.Label lbAv;
protected System.Web.UI.WebControls.Label lbExists;
SqlConnection con = new SqlConnection(@"Server=servername;DataBase=DataBaseName;uid=sa;pwd=sa;");

private void Page_Load(object sender, System.EventArgs e)
{
// Put user code to initialize the page here
if(!IsPostBack)
{
}
}

#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}
///

/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
///

private void InitializeComponent()
{
this.btCheck.Click += new System.EventHandler(this.btCheck_Click);
this.Load += new System.EventHandler(this.Page_Load);

}
#endregion

private void btCheck_Click(object sender, System.EventArgs e)
{
SqlDataAdapter da = new SqlDataAdapter(" select * from ScrTest",con);
DataSet ds = new DataSet();
da.Fill(ds,"ScrTest");
DataView dv = new DataView(ds.Tables["ScrTest"]);/*Represents a databindable, customized view of a DataTable for sorting, filtering, searching, editing, and navigation.*/
dv.RowFilter="emailid = '" + TextBox1.Text +"'";/*Gets or sets the expression used to filter which rows are viewed in the DataView*/
if(dv.Count >0)//If Count > 0 then Value Aavilable
{
lbExists.Visible=true;
lbAv.Visible=false;
}
else // Not Avaiable
{
lbAv.Visible=true;
lbExists.Visible=false;
}
}
}
}


DataBase Content


Avaiable Email Id

Exists Mail Id