C#: put an exe file on the foreground of the form

using System.Runtime.InteropServices;

public partial class FormMain : Form
{
    //
    // WINAPI definitions, copeied from windows.h
    enum SetWinPos_ZOrderOpt{HWND_TOP        = 0,
                                HWND_BOTTOM     = 1,
                                HWND_TOPMOST    = -1,
                                HWND_NOTOPMOST  = -2}
    enum SetWinPosFlags
    {
        SWP_NOSIZE = 0x0001,
        SWP_NOMOVE = 0x0002,
        SWP_NOZORDER = 0x0004,
        SWP_NOREDRAW = 0x0008,
        SWP_NOACTIVATE = 0x0010,
        SWP_FRAMECHANGED = 0x0020, /* The frame changed: send WM_NCCALCSIZE */
        SWP_SHOWWINDOW = 0x0040,
        SWP_HIDEWINDOW = 0x0080,
        SWP_NOCOPYBITS = 0x0100,
        SWP_NOOWNERZORDER = 0x0200, /* Don't do owner Z ordering */
        SWP_NOSENDCHANGING = 0x0400, /* Don't send WM_WINDOWPOSCHANGING */
        SWP_DRAWFRAME = SWP_FRAMECHANGED,
        SWP_NOREPOSITION = SWP_NOOWNERZORDER
    }

    //
    // Import SetWindowPos
    [DllImport("user32.dll", EntryPoint = "SetWindowPos")]
    public static extern IntPtr SetWindowPos(int hWnd, int hWndInsertAfter,
                                             int X, int Y, int cx, int cy,
                                             uint flages);

    // Start Notepad and set TOOPMOST
    private void buttonTestTopLevel_Click(object sender, EventArgs e)
    {
        Process myProcess = new Process();
        try
        {
            this.TopMost = false;
            string winpath = Environment.GetEnvironmentVariable("windir");
            myProcess.StartInfo.UseShellExecute = false;
            myProcess.StartInfo.FileName = winpath + @"\system32\notepad.exe";	// See Note 1
            myProcess.Start();
            myProcess.WaitForInputIdle();
            {
                // Here HWND_TOPMOST does it's Job
                SetWindowPos(myProcess.MainWindowHandle.ToInt32(), 
                                (int)SetWinPos_ZOrderOpt.HWND_TOPMOST,
                                0, 0, 0, 0,
                                (int)(SetWinPosFlags.SWP_NOSIZE |
                                      SetWinPosFlags.SWP_NOMOVE | 
                                      SetWinPosFlags.SWP_SHOWWINDOW));
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }
    // ...
}