Can I get the values of other application forms in Powershell?

$Win32=&{
Add-Type-Assembly "System.Runtime" 
# ========= Win32 Api function definition in C# language (from here) =========
$cscode=@" 

DllImport("user32.dll")]
static external IntPtr FindWindow (string lpClassName, string lpWindowName);
DllImport("user32.dll", SetLastError=true)]
public static external IntPtr FindWindowEx (IntPtr hwndParent, IntPtr hwndChildafter, string lpszClass, string lpszWindow);
DllImport("user32.dll", CharSet=CharSet.Unicode)
public static external int SendMessage (IntPtr hwnd, int msg, IntPtr wparam, IntPtr param);
DllImport("user32.dll", CharSet=CharSet.Unicode)
public static external int SendMessage (IntPtr hwnd, int msg, IntPtr wparam, System.Text.StringBuilder lparam);

public static IntPtr FindWindowByClass(string lpClassName){
    return FindWindow (lpClassName, null);
}

public static string GetText(IntPtr hwndParent, string lpszClass) {
    int WM_GETTEXT = 0x000D;
    intWM_GETTEXTLENGTH=0x000E;
    var hwnd=FindWindowEx(hwndParent, IntPtr.Zero, lpszClass, ''); // Control Handle
    Console.WriteLine(hwnd);
    var length = SendMessage (hwnd, WM_GETTEXTLENGTH, IntPtr.Zero, IntPtr.Zero); // Number of characters in the control
    Console.WriteLine(length);
    varsb = new System.Text.StringBuilder(length); /* Ensure buffer size for length*/
    SendMessage(hwnd, WM_GETTEXT, new IntPtr(length+1), sb);
    return sb.ToString();
}
"@
# ========= Win32 Api function definition in C# language (so far) =========

    return(add-type-memberDefinition$cscode-name "Win32ApiFunctions"-pasthru)
}
# Get Notepad Handle from Class Name
$notepad=$Win32::FindWindowByClass("notepad")
# Get Edit Control String
$s=$Win32::GetText($notepad, "Edit")
# display
$s