Say I have the following:
MyDate =
(db.MyTables.FirstOrDefault(x => x.MyID == idToFind).DateValue == DateTime.MinValue)
? DateTime.Now
: db.MyTables.FirstOrDefault(x => x.MyID == idToFind).DateValue
Is there any way to do this without running that LINQ query twice?
I cannot run it first into a temp variable because this query is itself part of a bigger LINQ query.
I cannot run it first into a temp variable because this query is itself part of a bigger LINQ query.
You can use a let assignment within your query (or alternatively a projection that includes a helper field if you are using lambda syntax - that's what it gets compiled down to anyway):
var query = from foo in db.Bar
let bar = db.MyTables.FirstOrDefault(x => x.MyID == idToFind).DateValue
select new
{
MyDate = bar == DateTime.MinValue ? DateTime.Now : bar
}
Yes.
var dateValue = db.MyTables.FirstOrDefault(x => x.MyID == idToFind).DateValue;
return dateValue == DateTime.MinValue ? DateTime.Now : dateValue;
Now, when you're saying that the value can't be stuffed into a temp value, what do you mean? The above code certainly looks to be able to converted to that pattern.
Evaluate once and assign to a variable - use the variable in your conditional:
var item = db.MyTables.FirstOrDefault(x => x.MyID == idToFind);
MyDate = (item.DateValue == DateTime.MinValue)
? DateTime.Now
: item.DateValue
Or:
var theDate = db.MyTables.FirstOrDefault(x => x.MyID == idToFind).DateValue;
MyDate = (theDate == DateTime.MinValue)
? DateTime.Now
: theDate
You can still use a temporary variable, declare it but assign it inside that expression. Lots of code might make it hard to read in some situations, but at least reduces duplication.
MyDate =
(temp = db.MyTables.FirstOrDefault(x => x.MyID == idToFind).DateValue) == DateTime.MinValue)
? DateTime.Now
: temp
Use LINQ's let statement
from a in someSource
let d = db.MyTables.FirstOrDefault(x => x.MyID == a.idToFind).DateValue
select (d == DateTime.MinValue) ? DateTime.Now : d;
