Show opened form mp_predracun C#

Question

name of form is mp_predracun

If opened show mp_predracun, else open new mp_predracun

 

private void PredracunToolStripMenuItem_Click(object sender, EventArgs e)
        {

            mp_predracun newMDIChild = new mp_predracun();
            newMDIChild.MdiParent = this;
            newMDIChild.Show();

        }