How to split the screen with 2 Open Forms within an MDI

Question

Good morning to you all. I have a question about forms. In my application, I can open 2 forms with grids where they present factory information. Those Grids are updated every 30 seconds, and are opened with:

StartPosition  --> WindowsDefaultLocation.
WindowState --> Normal
Size --> 1002;551

Doubt: I can boot them by making the Form1 open maximized, but on the restore button I can resize the Size of it to half the monitor screen? And form2 can identify if there is already an open form and resize Form2 to the second half of the screen with shows the example below.

It follows the code I’m working on, but incomplete, I’m testing the possibilities so it’s not functional, just a notion. I thought I’d use the event SizeChanged for that application.

    int lx, ly;
    int sw, sh;
    private void frm_Visualizar_Grid_SizeChanged(object sender, EventArgs e)
    {
        if (this.WindowState == FormWindowState.Minimized)
        {

            lx = this.Location.X;
            ly = this.Location.Y;
            sh = this.Size.Height;

            this.Size = Screen.PrimaryScreen.WorkingArea.Size;
            this.Location = Screen.PrimaryScreen.WorkingArea.Location;
        }
        frm_principal f = new frm_principal();
        if (this.WindowState == FormWindowState.Maximized)
        {                  
            //string cont = Application.OpenForms.Count.ToString();
            string cont = f.MdiChildren.Length.ToString();

            if (Convert.ToInt16(cont) < 2)
            {
                //sw = f.MdiParent.Size.Width;

                this.Size = new Size((sw / 2), sh);
                this.Location = new Point(lx,ly);
            }
            else
            {
                sw = f.MdiParent.Size.Width;
                this.Size = new Size((sw / 2), sh);
                //if (this.Location.IsEmpty)
                f.StartPosition = FormStartPosition.Manual;

            }
        }
    }

Thank you all.

---

I tried to apply the tip that our friend João Martins mentioned in the answer but I did not succeed.

    int lx, ly;
    int sw, sh;
    private void frm_Visualizar_Grid_SizeChanged(object sender, EventArgs e)
    {
        if (this.WindowState == FormWindowState.Minimized)
        {

            this.Size = Screen.PrimaryScreen.WorkingArea.Size;
            this.Location = Screen.PrimaryScreen.WorkingArea.Location;
        }
        if (this.WindowState == FormWindowState.Maximized)
        {
            //foreach (frm_Visualizar_Grid frm in MdiChildren)
            foreach (Form frm in Application.OpenForms)
            {
                this.LayoutMdi(System.Windows.Forms.MdiLayout.TileVertical);
            }
        }
    }

Answer 1

Try evoking the following method:

this.LayoutMdi(System.Windows.Forms.MdiLayout.TileVertical);

Will make all the MdiChild organize themselves vertically.