如何将XML块从一个文档复制到另一个文档?

I have two dataGridViews that load up an XML file each, I have made it so that you can drag and drop rows in between each of the grids. However at the moment, all that it does is copy the data from the dataGridView. This works fine however I need to copy all of the XML that is relevant to that row. I have two dataGridViews that load up an XML fi