Hi Peter,
Thank you for contacting Syncfusion Support
“Query #1: How do I set the selected items in ViewModel to UK and CA on startup for example?”
We have prepared a sample which tries to meet your requirement .In this sample, we have bound the first two items from the ObservableCollection to the SelectedItems collections property.
Please download the sample from the below link
Sample link:
ComboBoxadvSample“Query #2: how to load and save selected items.
We have bound the Checked ListBox SelectedItems to the ComboBoxAdv’s SelectedItems collection property in the button click event via command binding to achieve your requirement.
Please find the sample attached in the following link.
Sample:
ComboboxAdvSaveSampleRegards,
M.Sugapriya