I can use both code behind and java script for the button control
e.g
Login.aspx file with 2 text box and submit button Using java script to validate user name/pass word text box as like below:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Login.aspx.cs" Inherits="Login" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<script language = "javascript" >
function validate() {
if (document.getElementById("<%=txtUsername.ClientID%>").value == "") {
alert("User name cannot be blank");
document.getElementById("<%=txtUsername.ClientID%>").focus();
return false;
}
if (document.getElementById("<%=txtPassword.ClientID%>").value == "") {
alert("Password cannot be blank");
document.getElementById("<%=txtPassword.ClientID%>").focus();
return false;}
return true;}
</script>
<title></title>
</head>
<body>
<form runat="server" id = "LoginAuth" method ="post" >
<div>
UserName:
<asp:TextBox ID="txtUsername" runat="server"></asp:TextBox>
<br />
Password:
<asp:TextBox ID="txtPassword" runat="server"></asp:TextBox>
<br />
<asp:Button ID="cmdButton" runat="server" Text="Submit"
onclick="cmdButton_Click" />
</div>
<asp:Label ID="lblMsg" runat="server" ></asp:Label>
</form>
</body>
</html>
Login.aspx.cs
code behind file can have following code: to connect to db and add javascript function to the button control.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;//Configuration Manager
using System.Web.Security; //for FormAuthentication
public partial class Login : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
cmdButton.Attributes.Add("onclick", "return validate()");
}
protected void cmdButton_Click(object sender, EventArgs e)
{
if (Page.IsValid)
{
if (dbconn(txtUsername.Text.Trim(), txtPassword.Text.Trim())== true )
{
FormsAuthentication.RedirectFromLoginPage(txtUsername.Text, false );
}
else
{
lblMsg.Text = "Invalid UserName and Password€";
}
}
}
public bool dbconn(string u, string p)
{
SqlConnection conn = new SqlConnection();
conn.ConnectionString = ConfigurationManager.ConnectionStrings["NWConn"].ConnectionString;
conn.Open();
SqlCommand cmd = new SqlCommand("sp_ValidateUser", conn);
cmd.CommandType = CommandType.StoredProcedure;
SqlParameter userParam, passwordparam, retValueparam;
userParam = cmd.Parameters.Add("@UserName", SqlDbType.VarChar, 50) ;
passwordparam=cmd.Parameters.Add("QPassWord", SqlDbType.VarChar, 50);
retValueparam= cmd.Parameters.Add("@RetValue", SqlDbType.Int);
userParam.Direction = ParameterDirection.Input;
passwordparam.Direction = ParameterDirection.Input;
retValueparam.Direction = ParameterDirection.ReturnValue ;
userParam.Value = txtUsername.Text.ToString();
passwordparam.Value = txtPassword.Text.ToString();
//try
//{
if (conn.State == ConnectionState.Closed)
{
conn.Open();
cmd.ExecuteNonQuery();
}
//Obtain the return value of the stored procedure into a variable
int retValue = (int)retValueparam.Value;
if (retValue < 1)
{
return false ;
}
else
{
//Return true to indicate that the login is successful
return true;
}
//}
//catch (Exception ex)
//{
// lblMsg.Text = ex.Message + "Error connecting to DB";
//}
//return false;
}
}
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