private void button1_Click(object sender, EventArgs e)
{
if (child1 == null)
{
child1 = new Child1Form();
child1.MdiParent = this;
child1.Show();
}
}
private void button2_Click(object sender, EventArgs e)
{
if (child1 != null)
{
child1.Close();
child1.Dispose();
child1 = null;
}
}
