Change a Password in ASP.NET

Introduction

The registered user needs to login with his/her login credentials (user name and password). After successful login a Change password link will be visible. Here by clicking the link a new page will appear where the user must enter the Current Password, New Password and Confirm Password and then click on the Update button to change his/her password respectively.

Table structure

Now let's move to the coding part.

Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs"Inherits="Password_Change_in_asp.net._Default" %> <!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">    <title>Untitled Page</title></head>
<body>    <form id="form1" runat="server">    <div>
     <asp:Label ID="Label1" runat="server" Text="Name" Font-Bold="True"
            Width="100px" BackColor="#FFFF66" ForeColor="#FF3300"></asp:Label>        <asp:TextBox ID="TextBox_user_name" runat="server" ForeColor="#993300" Width="100px"></asp:TextBox><br />        <asp:Label ID="Label2" runat="server" Text="Password" Font-Bold="True"
            Width="100px" BackColor="#FFFF66" ForeColor="#FF3300"></asp:Label>        <asp:TextBox ID="TextBox_password" runat="server" ForeColor="#CC6600"
            TextMode="Password" Width="100px"></asp:TextBox><br />        <asp:Button ID="btn_login" runat="server" Text="Login" Font-Bold="True"
            BackColor="#CCFF99" onclick="btn_login_Click"  /><br />             <asp:Label ID="lb1" runat="server" Font-Bold="True" ForeColor="#FF3300"></asp:Label>    </div>
    </form></body>
</html>
Default.aspx.cs
using System;using System.Collections;using System.Configuration;using System.Data;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Xml.Linq;using System.Data.SqlClient;
namespace Password_Change_in_asp.net
{
    public partial class _Default : System.Web.UI.Page    {
        string strConnString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        string str = null;
        SqlCommand com;
        protected void btn_login_Click(object sender, EventArgs e)
        {
            object obj = null;
            SqlConnection con = new SqlConnection(strConnString);
            con.Open();

            Session["UserName"] = TextBox_user_name.Text;
            str = "select count(*) from login where UserName=@UserName and Password =@Password";
            com = new SqlCommand(str, con);
            com.CommandType = CommandType.Text;
            com.Parameters.AddWithValue("@UserName", Session["UserName"]);
            com.Parameters.AddWithValue("@Password", TextBox_password.Text);
            obj = com.ExecuteScalar();
            if ((int)(obj) != 0)
            {
                Response.Redirect("Welcome.aspx");
            }
            else            {
                lb1.Text = "Invalid Username and Password";
            }
            con.Close();
        }
    }
}

Welcome.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Welcome.aspx.cs"Inherits="Password_Change_in_asp.net.Welcome" %> <!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">    <title>Untitled Page</title></head>
<body>    <form id="form1" runat="server">    <div>     <asp:Label ID="lb1" runat="server" Font-Bold="True" ForeColor="#FF3300"></asp:Label><br />    </div>    <asp:LinkButton ID="lnk_changepassword" runat="server"
        onclick="lnk_changepassword_Click">Change Password</asp:LinkButton>    </form></body>
</html>
Welcome.aspx.cs
using System;using System.Collections;using System.Configuration;using System.Data;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Xml.Linq;
namespace Password_Change_in_asp.net
{
    public partial class Welcome : System.Web.UI.Page    {
        protected void Page_Load(object sender, EventArgs e)
        {
            lb1.Text = "WELLCOME :: " + Session["UserName"];
        }

        protected void lnk_changepassword_Click(object sender, EventArgs e)
        {
            Response.Redirect("Changepassword.aspx");
        }
    }
}

Changepassword.aspx<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Changepassword.aspx.cs"
Inherits="Password_Change_in_asp.net.Changepassword" %> <!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">    <title>Untitled Page</title></head>
<body>    <form id="form1" runat="server">    <div>
        <asp:Label ID="Label1" runat="server" Text="Current password" Width="120px"
            Font-Bold="True" ForeColor="#996633"></asp:Label>        <asp:TextBox ID="txt_cpassword" runat="server" TextMode="Password"></asp:TextBox>        <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
            ControlToValidate="txt_cpassword"
            ErrorMessage="Please enter Current password"></asp:RequiredFieldValidator>        <br />         <asp:Label ID="Label2" runat="server" Text="New password" Width="120px"
            Font-Bold="True" ForeColor="#996633"></asp:Label>        <asp:TextBox ID="txt_npassword" runat="server" TextMode="Password"></asp:TextBox>        <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server"
            ControlToValidate="txt_npassword" ErrorMessage="Please enter New password"></asp:RequiredFieldValidator>        <br />
         <asp:Label ID="Label3" runat="server" Text="Confirm password" Width="120px"
            Font-Bold="True" ForeColor="#996633"></asp:Label>
        <asp:TextBox ID="txt_ccpassword" runat="server" TextMode="Password"></asp:TextBox>

        <asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server"
            ControlToValidate="txt_ccpassword"
            ErrorMessage="Please enter Confirm password"></asp:RequiredFieldValidator>
        <asp:CompareValidator ID="CompareValidator1" runat="server"
            ControlToCompare="txt_npassword" ControlToValidate="txt_ccpassword"
            ErrorMessage="Password Mismatch"></asp:CompareValidator>
    </div>    <asp:Button ID="btn_update" runat="server" Font-Bold="True" BackColor="#CCFF99"onclick="btn_update_Click" Text="Update" />    <asp:Label ID="lbl_msg" Font-Bold="True" BackColor="#FFFF66" ForeColor="#FF3300" runat="server"Text=""></asp:Label><br />    <asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl="~/Default.aspx">Login</asp:HyperLink>    </form></body>
</html>
Changepassword.aspx.cs
using System;using System.Collections;using System.Configuration;using System.Data;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Xml.Linq;using System.Data.SqlClient;
namespace Password_Change_in_asp.net
{
    public partial class Changepassword : System.Web.UI.Page    {
        string strConnString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        string str = null;
        SqlCommand com;
        byte up;
        protected void btn_update_Click(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection(strConnString);
            con.Open();
            str = "select * from login ";
            com = new SqlCommand(str, con);
            SqlDataReader reader = com.ExecuteReader();
            while (reader.Read())
            {
                if (txt_cpassword.Text == reader["Password"].ToString())
                {
                    up = 1;
                }
            }
            reader.Close();
            con.Close();
            if (up == 1)
            {
                con.Open();
                str = "update login set Password=@Password where UserName='" + Session["UserName"].ToString()+ "'";
                com = new SqlCommand(str, con);
                com.Parameters.Add(new SqlParameter("@Password", SqlDbType.VarChar, 50));
                com.Parameters["@Password"].Value = txt_npassword.Text;
                com.ExecuteNonQuery();
                con.Close();
                lbl_msg.Text = "Password changed Successfully";
            }
            else            {
                lbl_msg.Text = "Please enter correct Current password";
            }
        }
    }
}
Output

Providing credentials (user name and password) for login: