如何将节点移动到所需位置？

I want to move a specific node (say i have the node reference), to a desired location (say to the top left corner of the canvas). I tried doing something similar to one in the sample project, where they move nodes while dragging with the mouse. But it doesn't seem to work. I am not seeing the node move as i expected. This is the code i have.I want to move a specific node (say i have the