Combine 2 linq operations

Question

Greetings I've got a logic question I have got 2 procedures

First is linq that looks like:

 _sharedDocumentsAttachments = SourceDocumentAttachmentMeta
 .Where(sDoc => TargetDocumentAttachmentMeta.Any(tDoc => tDoc.DocumentBridgeId == sDoc.DocumentId)).ToList();

Where

List<DocumentAttachment> _sharedDocumentsAttachments;

And

SharedDocumnentAttachmentConnector = new Dictionary<int, int>();
foreach (DocumentAttachment document in _sharedDocumentsAttachments)
{
    foreach (DocumentAttachment tDoc in TargetDocumentAttachmentMeta.Where(tDoc => document.DocumentId == tDoc.DocumentBridgeId))
    {
         SharedDocumnentAttachmentConnector.Add(document.DocumentId, tDoc.DocumentId);
    }
}

And I was wondering if I can attach second procedure to the first one somehow, as basically the are doing same compare but adding values to 2 different collections?

I was experimenting with for each but it wont work correctly.

score 2 · Accepted Answer · edited May 23 '17 at 11:51

You can do this: join the two collections and then specify how to convert to dictionary

_sharedDocumentsAttachments.Join(TargetDocumentAttachmentMeta,
                                 document => document.DocumentId,
                                 tDoc => tDoc.targetDocument,
                                 (document, tDoc) => new 
                                 { 
                                     Key = document.DocumentId, 
                                     Value = tDoc.DocumentId 
                                 })
                            .ToDictionary(item => item.Key,
                                          item => item.Value);

Take note that if the join will result with 2 "records" for the same document.DocumentId it will throw a ArgumentException: An item with the same key has already been added.

If that might happen then think of:

Saving it as a LookUp
Saving it as a Dictionary<int,IEnumerable<int>>

For differences between the two check this

Combine 2 linq operations

1 Answers1