C#

indianet wrote:

one bug is it does not have a semi-colon after window.open('');

public class Form1 : Form
{
    private const int WM_SETTINGCHANGE = 0x001A;

    public Form1()
    {
        InitializeComponent();
    }

    protected override void WndProc(ref Message m)
    {
        // This is a message code that is sent when system-wide setting is changed
        if (WM_SETTINGCHANGE == m.Msg)
        {
            if (m.LParam != IntPtr.Zero)
            {
                // Convert the LParam to string 
                string whatChanged = System.Runtime.InteropServices.Marshal.PtrToStringAuto(m.LParam);

                // Check if an Environment variable was changed 
                if (null != whatChanged && "Environment" == whatChanged)
                {
                    // Here goes the code that updates your application
                    MessageBox.Show("Environment variable changed");
                }
            }
        }
        // Don't forget to execute the message so the GUI will work.
        base.WndProc(ref m);
    }
}