c# - why always null get resource embedded file in sfx folder?

Question

why always get null get resource embedded file in my project 'Kriptografi'. My folder is sfx. I tried file in build action 'embedded resource'. Anyone can resolve it ? Thanks

void test() 
{
    var ConfigXml = "Kriptografi.sfx.Config.xml";
    Stream cfg = Assembly.GetExecutingAssembly().GetManifestResourceStream(ConfigXml);
    if (cfg == null)
    {
        MessageBox.Show("Nothing");
    }
    else 
    {
        MessageBox.Show("Exist"); 
    }
}