Click a button programatically C#

I am looking for a way to click a button programatically (Winform). I have a form (say Form2) and button (Button2) of my project. When I click my button it should click Button1 (which is in another project), but both are in same solution. This is what I tried to do:

private void button2(object sender, EventArgs e)
{

    System.IntPtr hwnd;

    System.IntPtr hwndChild = IntPtr.Zero;

    hwnd = FindWindow(null, "form1");

    if (hwnd.Equals(IntPtr.Zero))
    {
     MessageBox.Show("Couldn't find the form");
    }
    else
    {
    hwndChild = FindWindowEx((IntPtr)hwnd, IntPtr.Zero, null, "BUTTON1");

    if(!hwndChild.Equals(IntPtr.Zero))
    SendMessage(hwndChild, BM_CLICK, IntPtr.Zero, IntPtr.Zero);
    }
}

Should I use any other approach like reflection instead of this?