private void CreateFloorBelow()
{
ComboBoxItem_Z item = m_comboBox_z.Items[m_comboBox_z.Items.Count - 2] as ComboBoxItem_Z;
int newFloor = (item == null) ? -1 : item.Z - 1;
item = new ComboBoxItem_Z(newFloor);
m_comboBox_z.Items.Insert(m_comboBox_z.Items.Count - 1, item);
m_comboBox_z.SelectedItem = item;
}
private void CreateFloorAbove()
{
ComboBoxItem_Z item = m_comboBox_z.Items[1] as ComboBoxItem_Z;
int newFloor = (item == null) ? 0 : item.Z + 1;
item = new ComboBoxItem_Z(newFloor);
m_comboBox_z.Items.Insert(1, item);
m_comboBox_z.SelectedItem = item;
}