C# App. for sending a visual key "Enter" to a LABVIEW application

I want develop a C# App. for sending a visual key "Enter" to a LABVIEW application. This LABVIEW app. has a hot-key (ENTER) to execute function. So I need execute this function by my C# App. how I to do that?

I already use 2 methods, but not work

1)

IntPtr WindowToFind = FindWindow(null, "title name"); 
PostMessage(WindowToFind, WM_SYSKEYDOWN, VK_ENTER, 0);

2)

Process p = Process.GetProcessesByName("myApp").FirstOrDefault();
if (p != null)
{
IntPtr h = p.MainWindowHandle;
SetForegroundWindow(h);
SendKeys.SendWait("{ENTER}");
}

thank very much!!