How to query for items under @@id with specific @@templateid

Question

I'm trying to query a folder under the media library which has a bunch of templates based on a custom File template. I've tried to play around with a couple approaches but none of them have been successful.

I have tried:

1) Querying the entire media folder and grabbing all files based on the File template using the following line:

var files = SitecoreContext.Database.SelectItems($"fast:/sitecore/media library/*#[@@id = '{dcdFilesFolderId}']#//**#[@@tid = '{templateId}']#");

but this results in the error:

Sitecore.Data.Query.ParseException: End of string expected at position 77.

2) Query for a single item using the file ID:

var file = SitecoreContext.Database.SelectItem( $"fast:/sitecore/media library/*#[@@id = '{dcdFilesFolderId}']#//**[@File ID = '{fileid}']");

and this returns no hits.

What else can I try or make these queries work?

Answer 1

First: Don't use fast query, use your index (Sitecore.ContentSearch). "fast" query is actually very slow by comparison.

The query you tried is malformed, that's why you see this message:

Sitecore.Data.Query.ParseException: End of string expected at position 77.

It should look like this when the string is formatted:

/sitecore/media library//*[@@id='{43440D8E-E6AC-4F36-A5A5-53DB5CEFE369}']//*[@@templateid='{F44A8BAC-17C7-4A34-A84A-9B5F8CBBCEDC}']

1. //* will find all descendants
2. /* will find children (direct descendants)
3. '#' is used to escape item/field names. It is not necessary when you're using the attribute tokens (e.g.: @@id, @@templateid
4. It's @@templateid, not @@tid

The Sitecore Query Cheat Sheet is handy (and still relevant)

There's also a Xpath Builder tool that you can use to test out your queries. This has been inexplicably removed from the the sitecore interface/navigation/control panel but you can get to it directly from here: http://[SiteUrl]/sitecore/shell/default.aspx?xmlcontrol=IDE