Graph API query - how to combine expand and select

Question

I have the following working code, that lists all files in a Sharepoint site and also grabs their driveItem details:

        var directoryContents = await App.GraphClient.Sites[SiteIdShortName].Lists[sharedDocsDriveId]
            .Items
            .Request()
            .Expand(item => item.DriveItem)
            .GetAsync();
        SharedDocumentList.ItemsSource = directoryContents.CurrentPage.ToList();

Now I need a way to also grab the publication status for each item, in additional to the data the above query is already getting. I found this post here on stackoverflow:

checkout status of a onedrive file using microsoft graph api

So I've tried to change my code to look like this:

        var directoryContents = await App.GraphClient.Sites[SiteIdShortName].Lists[sharedDocsDriveId]
            .Items
            .Request()
            .Expand(item => item.DriveItem)
            .Select(item => item.DriveItem.Publication)
            .GetAsync();
        SharedDocumentList.ItemsSource = directoryContents.CurrentPage.ToList();

But I'm getting the following error message:

Message=Anonymous type in lambda expression may only be initialized with direct members of type ListItem Parameter name: selectExpression Source=Microsoft.Graph

EDIT 1

I also tried this:

        var queryOptions = new List<QueryOption>()
        {
            new QueryOption("select", "publication")
        };

        var directoryContents = await App.GraphClient.Sites[SiteIdShortName].Lists[sharedDocsDriveId]
            .Items
            .Request(queryOptions)
            .Expand(item => item.DriveItem)
            .GetAsync();
        SharedDocumentList.ItemsSource = directoryContents.CurrentPage.ToList();

But the error I get is:

Inner Exception 1: JsonReaderException: '{' is invalid after a value. Expected either ',', '}', or ']'. LineNumber: 0 | BytePositionInLine: 223.

Answer 1

This works for me. In Expand I've specified the property to be expanded with select statement which specified property inside the driveItem

var directoryContents = await App.GraphClient.Sites[SiteIdShortName].Lists[sharedDocsDriveId]
        .Items
        .Request()
        .Expand("driveItem($select=publication)")
        .GetAsync();
SharedDocumentList.ItemsSource = directoryContents.CurrentPage.ToList();