private void strataListView1_SelectedItemChanged(object sender, EventArgs e)
        {
           
            if (strataListView1.SelectedItems[0].Selected == true)
            {
                this.toolStripButtonEdit.Enabled = true;
                this.toolStripButtonDelete.Enabled = true;
            }
            else
            {
                this.toolStripButtonEdit.Enabled = false;
                this.toolStripButtonDelete.Enabled = false;
            }
         }

NB. With the standard strataframe listview I used this code

  private void listView_SelectedIndexChanged(object sender, EventArgs e)
        {

            this.toolStripButtonEditGroup.Enabled = listView.SelectedItems.Count > 0;
            this.toolStripDeleteGoup.Enabled = listView.SelectedItems.Count > 0;

        }