C#

private void ChildFillClientArea()
{
    if (ActiveMdiChild !=null)
    {
        Form activeChild = ActiveMdiChild;
        Rectangle clientArea = Rectangle.Empty;
        foreach (Control control in this.Controls)
        {
            if (control is MdiClient) clientArea = control.ClientRectangle;
        }
        activeChild.Bounds = clientArea;
    }
}

MonitorRiscoResultadoFrm frmMonitor = new MonitorRiscoResultadoFrm();
frmMonitor.MdiParent = this;
frmMonitor.Show();
ChildFillClientArea();

Alan Balkany wrote:

VS6 is Visual Studio version 6. It was followed by Visual Studio .NET in 2003. After that Microsoft identified compiler versions by the year they were released, e.g. VS 2008.

Form1 frm = new Form1();
frm.BackColor = Color.FromArgb(255,0,255);
frm.TransparencyKey = Color.FromArgb(255,0,255);
frm.Show();