If you want to be able to export all items you must ensure that they are loaded. For example, if your ViewModel has a VirtualQueryableCollectionView called View, you can do this in the following way:
var viewModel =
To better demonstrate this, I'm attaching a sample project for you to have a look at.
Bear in mind that this will lead to poor performance when dealing with large amounts of data.
As for your second question, I will ask you to provide more information in order to better understand, what exactly do you have in mind.
I hope you find this information helpful.
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