[C#] 실행중인 Child Form 개수 설정

private Form[] fTemp; 
 
private void frmMdi_Load(object sender, EventArgs e)
{
    try
    {
        ChildForm_DisplayCount();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}
 
 
private void ChildForm_DisplayCount()
{
    this.MdiChildActivate += new EventHandler(frmMDI_MdiChildActivate);
}
 
void frmMDI_MdiChildActivate(object sender, EventArgs e)
{
    fTemp = this.MdiChildren;
 
    if (fTemp.Length > 4)
    {
        fTemp[1].Close();
    }
}