You can do this with the help of Form sizechanged event.
public Form1()
{ InitializeComponent();
this.SizeChanged += new EventHandler(form1_sizeeventhandler);
}
private void form1_sizeeventhandler(object sender, EventArgs
e)
{
if (this.WindowState
== FormWindowState.Minimized)
{
MessageBox.Show("Form is mininized");
// handle it
}
if (this.WindowState
== FormWindowState.Normal)
{
MessageBox.Show("Form is restored");
// handle it
}
if (this.WindowState
== FormWindowState.Maximized)
{
MessageBox.Show("Form is maximized");
// handle it
}
}