Form doesn't open on MDI Form

Hi All,
This is my Scenario. In my Application, I have MDI Form, Form1 and Form2. These two forms opened on the MDI Form. I called that form from the MDI Menu. First I opened Form1 on the MDI Form . Datagridview is on the Form1. when I double clicked the datagridview , Form2 should show on the MDI . This is my Code,

On MDI Menu Bar

Form1 frm = new Form1();
            frm.MdiParent = this;
            frm.WindowState = FormWindowState.Maximized;
            frm.Show();

Form2 frm1 = new Form2();
            frm1.MdiParent = this;
            frm1.WindowState = FormWindowState.Maximized;

            frm1.Show();

private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
        {
            MDIParent1 mdi = new MDIParent1();
            Form2 frm = new Form2();
            frm.MdiParent = mdi;
            frm.WindowState = FormWindowState.Maximized;
            frm.Show();
        }

But Form2 doesn't open on the MDI Form. Please let me know where is this problem? and how can i solve this issue?

Regards,
Lakshmi Naraayanan.S
http://dotnettechrocks.blogspot.in/
http://abaprocker.blogspot.com/