How to Insert Chlid Form Textbox Values on Mdi Parent Menu Click event ?

I Have One Mdi Parent Form and Child Form.I want to save Child form Text box values on mdi parent Menu Button Click Event? i already write the coding but it not working 

Mdi Parent Form

  private void toolStripButton2_Click(object sender, EventArgs e)
        {
            Sample Examplesave = new Sample();
            Form ActiveForm = this.ActiveMdiChild as Form;
            Examplesave.save();
}

Child Form

public void save()
       {
           //Form ODTurning = this.ActiveMdiChild;
           strField = "VC,FP_REV,MAX_DIA,MIN_DIA,LENGTH,D_DUT,RPM,F_MIN,N_PASS,OD_CYCLE,CREATED_DT";

           strValue = "'" + Vc.Text + "','" + FeedPerRev.Text + "'";

           result = objDO.Saveop("Tbl_TURN", strField, strValue);

           if (result == true)
           {
               MessageBox.Show("INSERTED SUCCESSFULLY");
           }
           else
           {
               MessageBox.Show("Please verify your answer");

           }
          // btnODTsave.PerformClick();

       }

I open Child form and give the inputs of two text boxs(vc.text,feedperrev.text) but values didn't pass the values on this method. please give the examples or some tips. Thanks