如何将两个XML文件与c#合并

I have two XML files and I want to merge this two files to one. But how? I have tried a lot but nothing helps. As you can see the merged XML has left the text from the second attribute if it came from the first XML. Second the Element have to be ordered by there Id/Name/whatevername the first attribute have. Third if a node doesn't exist in XML 2 then it has to be created at the same place as in XML 1.I have two XML files and I want to merge this t