How to create a Link in a Node?

Similar to the above image.

I also have a question about group, can I fix fixed group when moving subgraph?

Yes, that is accomplished by using Groups. It appears that that Group DataTemplate has one input port and 3 output ports.

So,How do I creat a Link in a Node or Group?(Inner line)

All of the Links that you show in that screenshot are just regular links. That Node must be a member of that Group, though.

Let me give an example: I have a node called ‘m1’, it has a left port ‘L1’ and a right port ‘R1’, how should I build a connection between L1 and R1 through the Line (I call this ‘InnerLine’).

The GoXamIntro.pdf document has a section about “Ports on Nodes” that discusses how links can connect to specific port elements rather than to the whole node.

That document has a section about “Data Templates for Groups” that talks about group templates. You’ll note that it discusses ports that are on groups, since groups are just fancy nodes.

There are a lot of examples that have nodes that have separate ports. In your case I assume that “m1” is the Group node. You’d have a link data object that would have properties like:

 new MyLinkData() { From="m1", FromPort="L1", To="m1", ToPort="R1" }