Here is the point where you need to get a reminded that you are a software developer. Even if you used some code sample, you should have understood how it works instead of using it as a cookbook recipe. You need to be able to write code, not take fragments of code here and there trying to put them together using trial-and-error "method". And you need to get a habit to write code from scratch to the requirements, using library code (and creating such libraries, growing your algorithmic repertoire), not pieces of application. Software reuse means developing and using libraries, not copy-and-paste.
Let me tell you that there is no principal difference between one or more grid views. If you see a problem in "converting" single grid view code into multiple, you just don't even try to do any professional chores. Besides, you should understand that there is no such thing as "just XML" which you can write. There are different data models which can be created to different application, and their structures can be expressed as some meta-data, which corresponds to one or another XML schema. The same application data representation can be modeled in a number of different ways giving different schemes.
Besides, it's possible that the code samples you saw were not good. You should not have code saving some UI state in XML file, not when UI expresses some data set. Instead, you need to isolate UI from data model, and data model from persistence. In the simplest case, you can have an instance of a data model in memory and have procedures for populating UI from data, and modifying data from UI state. And the data, not UI, should be uses for persistence. Everything is already done for you, as you can use Data Contract
which will allow you to avoid dealing with XML directly. Please see:
Please also see my past answers where I advocate this approach:
How can I utilize XML File streamwriter and reader in my form application?
Creating property files...