6 ms·

Slight aside: please don't abuse the Elvis operator like that (by using it on every single nullable reference), it could easily grow into a widespread anti-patt

by piaste 10y ago

Slight aside: please don't abuse the Elvis operator like that (by using it on every single nullable reference), it could easily grow into a widespread anti-pattern that makes debugging harder. My rule of thumb is that ?. is OK to use when 1) The reference is expected to occasionally be null in the course of normal operations 2) You legitimately don't care if the reference is unexpectedly null, as you wouldn't or couldn't fix it even if you knew about it Otherwise it's better to discover and fix the NullReferenceException ASAP.

perezdev 10y ago
It's the null propagation operator.
- breischl 10y ago
  Look, if you want to be pedantic it's the null conditional operator[1]. But it is widely called the "Elvis operator"[2]. [1] - https://msdn.microsoft.com/en-us/library/dn986595.aspx https://msdn.microsoft.com/en-us/library/dn986595.aspx [2] - https://www.google.com/#q=c%23+elvis+operator https://www.google.com/#q=c%23+elvis+operator
gregmac 10y ago
Generally agreed, and out of curiosity I just looked through some fairly new code I have that's pretty heavy on C# 6, and only found a single instance of two null conditionals being used: Assert.That(r.Exception?.InnerException?.Message, Is.EqualTo("Exception result")); Next closest thing that shows up a few times is coalescing to a default value: config?.OutputName ?? DefaultConfig.OutputName Some other examples that show up a lot: Invoke Action<> or Func<> that may be null or unassigned (this works for Events as well): actionHandler?.Invoke(value); Extracting a value from a LINQ expression on a list of container objects (this one is actually from a unit test where it's explicitly only expecting one item): items.First()?.Data Easy way to do a Coalesce on a specific property value in a collection: items.FirstOrDefault(item => item.Data != null)?.Data
- piaste 10y ago
  items.First()?.Data I think this one doesn't do anything because .First() will throw on an empty collection. The rest of your samples look fine to me though.

by piaste 10y ago

perezdev 10y ago

It's the null propagation operator.

breischl 10y ago
Look, if you want to be pedantic it's the null conditional operator[1]. But it is widely called the "Elvis operator"[2]. [1] - https://msdn.microsoft.com/en-us/library/dn986595.aspx https://msdn.microsoft.com/en-us/library/dn986595.aspx [2] - https://www.google.com/#q=c%23+elvis+operator https://www.google.com/#q=c%23+elvis+operator

gregmac 10y ago

Generally agreed, and out of curiosity I just looked through some fairly new code I have that's pretty heavy on C# 6, and only found a single instance of two null conditionals being used: Assert.That(r.Exception?.InnerException?.Message, Is.EqualTo("Exception result")); Next closest thing that shows up a few times is coalescing to a default value: config?.OutputName ?? DefaultConfig.OutputName Some other examples that show up a lot: Invoke Action<> or Func<> that may be null or unassigned (this works for Events as well): actionHandler?.Invoke(value); Extracting a value from a LINQ expression on a list of container objects (this one is actually from a unit test where it's explicitly only expecting one item): items.First()?.Data Easy way to do a Coalesce on a specific property value in a collection: items.FirstOrDefault(item => item.Data != null)?.Data

piaste 10y ago
items.First()?.Data I think this one doesn't do anything because .First() will throw on an empty collection. The rest of your samples look fine to me though.