Hello,
Currently we pull all information back and filter it to get single records like this:
(await _userRepository.GetAllListAysnc()).FirstOrDefault(x => x.name == "Bob");
We would like to only pull back the information we need and write something like this:
_userRepository.GetAsync(x => x.name == "Bob")
or
_userRepository.GetAsync().Where(x => x.name == "Bob")
Is this possible? We see this project doing something similar: [https://github.com/zzzprojects/LINQ-Async])
Thank you for your time.
4 Answer(s)
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0
Yes, this is possible:
var bob = await _userRepository.FirstOrDefaultAsync(x => x.Name == "Bob"); -
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Hi Aaron,
Thank you for your reply. My example was probably too simple. Your answer will indeed help in some places. A real example of our code is:
var temporaryConflicts = (await _enrollmentRepository.GetAllListAsync()) .Where(x => x is Temporary) .Where(x => !excludedIds.Contains(x.Id)) .GroupBy(x => x.Detail.Username) .Where(g => g.Count() > 1) .Select(g => g.Key);We would like something like this:
var temporaryConflicts = _enrollmentRepository.GetAllListAsync() .WhereAsync(x => x is Temporary) .WhereAsync(x => !excludedIds.Contains(x.Id)) .GroupByAsync(x => x.Detail.Username) .WhereAsync(g => g.Count() > 1) .Select(g => g.Key);This way the filtering is done when the data is acquired (DB level) and not done afterwards (in memory).
Thanks!
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Use ToListAsync. Linq-to-SQL is compiled, so Where and GroupBy do not need async counterparts.
var temporaryConflicts = await _enrollmentRepository.GetAll() .Where(x => x is Temporary) .Where(x => !excludedIds.Contains(x.Id)) .GroupBy(x => x.Detail.Username) .Where(g => g.Count() > 1) .Select(g => g.Key) .ToListAsync(); -
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@Aaron
Thank you.
The
.FirstOrDefaultAsync()and
.GetAll()...ToListAsync()methods are exactly what we needed.
And these changes should significantly speed up some of our methods.
