Using GraphLinksModel and LayeredDigraphLayout, but all links are not shown

Hi, as I am using GraphLinksModel and LayeredDigraphLayout, I find that after I add data nodes and links into the nodessource and linksource, it just does not show the expected graph. All datanode are displayed as expected, but all the links are not visible. I’ve debugged while running, the node source has all nodes that I want to add. And linksource has all links with right “from” and “to”.

Never mind. It turns out to be my fault.