ChangePassword.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Coders_Space
{
    public partial class ChangePassword : Form
    {
        string cs = ConfigurationManager.ConnectionStrings["dbcs"].ConnectionString;
        string userEmail;
        public ChangePassword(string email)
        {
            InitializeComponent();
            userEmail = email;
        }

        private void changepasswordBtn_Click(object sender, EventArgs e)
        {
            string oldPassword = textBoxOldPassword.Text;
            string newPassword = textBoxNewPassword.Text;
            string confirmPassword = textBoxConfirmNewPassword.Text;

            if (string.IsNullOrEmpty(oldPassword) || string.IsNullOrEmpty(newPassword) || string.IsNullOrEmpty(confirmPassword))
            {
                MessageBox.Show("Please fill in all fields.");
                return;
            }

            if (newPassword != confirmPassword)
            {
                MessageBox.Show("New password and confirm password do not match.");
                return;
            }

            UpdatePassword(userEmail, oldPassword, newPassword);
        }
        private void UpdatePassword(string email, string oldPassword, string newPassword)
        {
            using (SqlConnection con = new SqlConnection(cs))
            {
                try
                {
                    con.Open();
                    string query = "UPDATE USERS SET PASSWORD = @NewPassword WHERE EMAIL = @Email AND PASSWORD = @OldPassword";
                    SqlCommand cmd = new SqlCommand(query, con);
                    cmd.Parameters.AddWithValue("@Email", email);
                    cmd.Parameters.AddWithValue("@OldPassword", oldPassword);
                    cmd.Parameters.AddWithValue("@NewPassword", newPassword);

                    int rowsAffected = cmd.ExecuteNonQuery();

                    if (rowsAffected > 0)
                    {
                        MessageBox.Show("Password changed successfully.");
                        textBoxOldPassword.Clear();
                        textBoxNewPassword.Clear();
                        textBoxConfirmNewPassword.Clear();
                    }
                    else
                    {
                        MessageBox.Show("Invalid old password. Password not changed.");
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Error: " + ex.Message);
                }
            }
        }

        private void exitBTN_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }
}