How do I use Google.GData.Client.AtomLinkCollection.FindService method to get the list of worksheets in a Google Spreadsheet?

Question

I'm trying to write code that talks to Google Spreadsheets. We do a bunch of processing on our end and then pass data out to our client into this spreadsheet and I want to automate it. This seems like it should be easy.

On this page, Google says "Given a SpreadsheetEntry you've already retrieved, you can print a list of all worksheets in this spreadsheet as follows:"

AtomLink link = entry.Links.FindService(GDataSpreadsheetsNameTable.WorksheetRel, null);

WorksheetQuery query = new WorksheetQuery(link.HRef.ToString());
WorksheetFeed feed = service.Query(query);

foreach (WorksheetEntry worksheet in feed.Entries)
{
    Console.WriteLine(worksheet.Title.Text);
}

Following along at home, I start with:

Dim link As AtomLink = Entry.Links.FindService(GDataSpreadsheetsNameTable.WorksheetRel, "")
Dim wsq As New WorksheetQuery(link.HRef.ToString)

and when execution gets to that second line, I find that "Object reference not set to instance of an object." The FindService method is returning nothing. And when I look at GDataSpreadsheetsNameTable.WorksheetRel, it's a constant value of "http://schemas.google.com/spreadsheets/2006#worksheetsfeed"

I'm not really at the point where I even grok what it wants to be doing. E.g., what's a feed? Is a worksheet really what I think it is based on Excel nomenclature? That kind of stuff. But I see a couple of things that might be causing my issue:

1. The C# method call "...FindService(GDataSpreadsheetsNameTable.WorksheetRel, null);" I'm not sure about that null. It demands a string, so I used "" in my VB, but I'm not sure that's right.
2. That schemas.google.com URI doesn't seem to be live. At least, if I punch it into a browser, I get server not found. But again, I don't exactly know what it's trying to do.

So, any thoughts? Anyone have VB code that reads Google Spreadsheets and time to instruct a newbie? I'm surprised to find that there's essentially no useful sample code floating around the net.

Thanks for reading!

Answer 1

So, of course, right after I posted this I found some inspiration over here. Manually iterating across the collections works just fine, even if it's not the preferred way to do this. I'm still keen to hear info from others related to this, so feel encouraged to help out even though I'm maybe over this one hurdle.

For Each Entry In mySprShFeed.Entries
    If Entry.Title.Text = "spreadsheetNameSought" Then
        For Each link As AtomLink In Entry.Links
            If link.Rel = GDataSpreadsheetsNameTable.WorksheetRel Then
                Dim wsf As WorksheetFeed = service.Query(New WorksheetQuery(link.HRef.ToString))
                For Each worksheet In wsf.Entries
                    Console.WriteLine(worksheet.Title.Text)
                Next

            End If
        Next
    End If
Next