MainForm.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace AD_Authentication
{
    public partial class MainForm : Form
    {

        public string loggedInUser
        {
            get
            {
                return this.lblLogin.Text;
            }
            set
            {
                this.lblLogin.Text = value;
            }
        }

        public MainForm()
        {
            InitializeComponent();
        }

        private void btnLogin_Click(object sender, EventArgs e)
        {
            LoginForm login = new LoginForm();
            login.ShowDialog(this);
        }

        private void btnGetUsers_Click(object sender, EventArgs e)
        {
            ADUsersForm _adUsers = new ADUsersForm();
            _adUsers.ShowDialog(this);
        }

        private void btnGetUserDetails_Click(object sender, EventArgs e)
        {
            UserSearchForm _usrSrch = new UserSearchForm();
            _usrSrch.ShowDialog(this);
        }
    }
}