How can I set the property value to 0 if the referenced model is NULL?
I'm calculating the value for WageCost in ScheduleWeek from ScheduleDays like this (the property name is the same for wage cost in a day and in a week):
public double WageCost => ScheduleDays.Sum(w => w.WageCost);
But if ScheduleDays is null, I get an exception. How can I set the value of WageCost to 0 if no ScheduleDays exist?
c#
asked Nov 15 '18 at 13:27
StianStian
339213
add a comment |
I'm calculating the value for WageCost in ScheduleWeek from ScheduleDays like this (the property name is the same for wage cost in a day and in a week):
public double WageCost => ScheduleDays.Sum(w => w.WageCost);
But if ScheduleDays is null, I get an exception. How can I set the value of WageCost to 0 if no ScheduleDays exist?
c#
asked Nov 15 '18 at 13:27
StianStian
339213
8
ScheduleDays?.Sum(w => w.WageCost) ?? 0;
– SeM
Nov 15 '18 at 13:29
Write a check for null. SeM gave you the new null-conditional opeartor wich isa convencience feature that was added with C# 6 or so. But a good oldif(ScheduleDays == null) WageCost = 0;would also work.
– Christopher
Nov 15 '18 at 13:30
@Christopher If I remember correctly, expression bodied properties was added in c#6. So I assumed he is using >=c#6.
– SeM
Nov 15 '18 at 13:34
@SeM: It is a solid asumption that anyone has access to those right now. I was just mentioning it for completeness.
– Christopher
Nov 15 '18 at 13:38
add a comment |
I'm calculating the value for WageCost in ScheduleWeek from ScheduleDays like this (the property name is the same for wage cost in a day and in a week):
public double WageCost => ScheduleDays.Sum(w => w.WageCost);
But if ScheduleDays is null, I get an exception. How can I set the value of WageCost to 0 if no ScheduleDays exist?
c#
asked Nov 15 '18 at 13:27
StianStian
339213
I'm calculating the value for WageCost in ScheduleWeek from ScheduleDays like this (the property name is the same for wage cost in a day and in a week):
public double WageCost => ScheduleDays.Sum(w => w.WageCost);
But if ScheduleDays is null, I get an exception. How can I set the value of WageCost to 0 if no ScheduleDays exist?
c#
c#
asked Nov 15 '18 at 13:27
StianStian
339213
asked Nov 15 '18 at 13:27
StianStian
339213
asked Nov 15 '18 at 13:27
StianStian
339213
asked Nov 15 '18 at 13:27
StianStian
339213
asked Nov 15 '18 at 13:27
StianStian
339213
339213
8
ScheduleDays?.Sum(w => w.WageCost) ?? 0;
– SeM
Nov 15 '18 at 13:29
Write a check for null. SeM gave you the new null-conditional opeartor wich isa convencience feature that was added with C# 6 or so. But a good oldif(ScheduleDays == null) WageCost = 0;would also work.
– Christopher
Nov 15 '18 at 13:30
@Christopher If I remember correctly, expression bodied properties was added in c#6. So I assumed he is using >=c#6.
– SeM
Nov 15 '18 at 13:34
@SeM: It is a solid asumption that anyone has access to those right now. I was just mentioning it for completeness.
– Christopher
Nov 15 '18 at 13:38
add a comment |
8
ScheduleDays?.Sum(w => w.WageCost) ?? 0;
– SeM
Nov 15 '18 at 13:29
Write a check for null. SeM gave you the new null-conditional opeartor wich isa convencience feature that was added with C# 6 or so. But a good oldif(ScheduleDays == null) WageCost = 0;would also work.
– Christopher
Nov 15 '18 at 13:30
@Christopher If I remember correctly, expression bodied properties was added in c#6. So I assumed he is using >=c#6.
– SeM
Nov 15 '18 at 13:34
@SeM: It is a solid asumption that anyone has access to those right now. I was just mentioning it for completeness.
– Christopher
Nov 15 '18 at 13:38
8
8
ScheduleDays?.Sum(w => w.WageCost) ?? 0;– SeM
Nov 15 '18 at 13:29
ScheduleDays?.Sum(w => w.WageCost) ?? 0;– SeM
Nov 15 '18 at 13:29
Write a check for null. SeM gave you the new null-conditional opeartor wich isa convencience feature that was added with C# 6 or so. But a good old
if(ScheduleDays == null) WageCost = 0; would also work.– Christopher
Nov 15 '18 at 13:30
Write a check for null. SeM gave you the new null-conditional opeartor wich isa convencience feature that was added with C# 6 or so. But a good old
if(ScheduleDays == null) WageCost = 0; would also work.– Christopher
Nov 15 '18 at 13:30
@Christopher If I remember correctly, expression bodied properties was added in c#6. So I assumed he is using >=c#6.
– SeM
Nov 15 '18 at 13:34
@Christopher If I remember correctly, expression bodied properties was added in c#6. So I assumed he is using >=c#6.
– SeM
Nov 15 '18 at 13:34
@SeM: It is a solid asumption that anyone has access to those right now. I was just mentioning it for completeness.
– Christopher
Nov 15 '18 at 13:38
@SeM: It is a solid asumption that anyone has access to those right now. I was just mentioning it for completeness.
– Christopher
Nov 15 '18 at 13:38
add a comment |
2 Answers
2
active
oldest
votes
You can use ?(null-conditional) and ??(null-coalescing) operators for that:
public double WageCost => ScheduleDays?.Sum(w => w.WageCost) ?? 0;
References: ?? Operator , ?. and ? null-conditional Operators
answered Nov 15 '18 at 13:31
SeMSeM
4,43711529
Thanks! Antoine V has almost the same answer, and answered one minute before you did, but I'm accepting yours because of the reference links and because Antoine has more rep than you. ;)
– Stian
Nov 16 '18 at 8:19
@Stian You're welcome, and thanks :)
– SeM
Nov 16 '18 at 8:20
add a comment |
Double verification
? for w?.WageCost : avoid NullException
?? for ScheduleDays : if null, takes 0 as value
public double WageCost => ScheduleDays?.Sum(w => w?.WageCost) ?? 0;
answered Nov 15 '18 at 13:29
Antoine VAntoine V
5,1262424
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
You can use ?(null-conditional) and ??(null-coalescing) operators for that:
public double WageCost => ScheduleDays?.Sum(w => w.WageCost) ?? 0;
References: ?? Operator , ?. and ? null-conditional Operators
answered Nov 15 '18 at 13:31
SeMSeM
4,43711529
Thanks! Antoine V has almost the same answer, and answered one minute before you did, but I'm accepting yours because of the reference links and because Antoine has more rep than you. ;)
– Stian
Nov 16 '18 at 8:19
@Stian You're welcome, and thanks :)
– SeM
Nov 16 '18 at 8:20
add a comment |
You can use ?(null-conditional) and ??(null-coalescing) operators for that:
public double WageCost => ScheduleDays?.Sum(w => w.WageCost) ?? 0;
References: ?? Operator , ?. and ? null-conditional Operators
answered Nov 15 '18 at 13:31
SeMSeM
4,43711529
Thanks! Antoine V has almost the same answer, and answered one minute before you did, but I'm accepting yours because of the reference links and because Antoine has more rep than you. ;)
– Stian
Nov 16 '18 at 8:19
@Stian You're welcome, and thanks :)
– SeM
Nov 16 '18 at 8:20
add a comment |
You can use ?(null-conditional) and ??(null-coalescing) operators for that:
public double WageCost => ScheduleDays?.Sum(w => w.WageCost) ?? 0;
References: ?? Operator , ?. and ? null-conditional Operators
answered Nov 15 '18 at 13:31
SeMSeM
4,43711529
You can use ?(null-conditional) and ??(null-coalescing) operators for that:
public double WageCost => ScheduleDays?.Sum(w => w.WageCost) ?? 0;
References: ?? Operator , ?. and ? null-conditional Operators
answered Nov 15 '18 at 13:31
SeMSeM
4,43711529
edited Nov 15 '18 at 13:37
answered Nov 15 '18 at 13:31
SeMSeM
4,43711529
answered Nov 15 '18 at 13:31
SeMSeM
4,43711529
answered Nov 15 '18 at 13:31
SeMSeM
4,43711529
4,43711529
Thanks! Antoine V has almost the same answer, and answered one minute before you did, but I'm accepting yours because of the reference links and because Antoine has more rep than you. ;)
– Stian
Nov 16 '18 at 8:19
@Stian You're welcome, and thanks :)
– SeM
Nov 16 '18 at 8:20
add a comment |
Thanks! Antoine V has almost the same answer, and answered one minute before you did, but I'm accepting yours because of the reference links and because Antoine has more rep than you. ;)
– Stian
Nov 16 '18 at 8:19
@Stian You're welcome, and thanks :)
– SeM
Nov 16 '18 at 8:20
Thanks! Antoine V has almost the same answer, and answered one minute before you did, but I'm accepting yours because of the reference links and because Antoine has more rep than you. ;)
– Stian
Nov 16 '18 at 8:19
Thanks! Antoine V has almost the same answer, and answered one minute before you did, but I'm accepting yours because of the reference links and because Antoine has more rep than you. ;)
– Stian
Nov 16 '18 at 8:19
@Stian You're welcome, and thanks :)
– SeM
Nov 16 '18 at 8:20
@Stian You're welcome, and thanks :)
– SeM
Nov 16 '18 at 8:20
add a comment |
Double verification
? for w?.WageCost : avoid NullException
?? for ScheduleDays : if null, takes 0 as value
public double WageCost => ScheduleDays?.Sum(w => w?.WageCost) ?? 0;
answered Nov 15 '18 at 13:29
Antoine VAntoine V
5,1262424
add a comment |
Double verification
? for w?.WageCost : avoid NullException
?? for ScheduleDays : if null, takes 0 as value
public double WageCost => ScheduleDays?.Sum(w => w?.WageCost) ?? 0;
answered Nov 15 '18 at 13:29
Antoine VAntoine V
5,1262424
add a comment |
Double verification
? for w?.WageCost : avoid NullException
?? for ScheduleDays : if null, takes 0 as value
public double WageCost => ScheduleDays?.Sum(w => w?.WageCost) ?? 0;
answered Nov 15 '18 at 13:29
Antoine VAntoine V
5,1262424
Double verification
? for w?.WageCost : avoid NullException
?? for ScheduleDays : if null, takes 0 as value
public double WageCost => ScheduleDays?.Sum(w => w?.WageCost) ?? 0;
answered Nov 15 '18 at 13:29
Antoine VAntoine V
5,1262424
answered Nov 15 '18 at 13:29
Antoine VAntoine V
5,1262424
answered Nov 15 '18 at 13:29
Antoine VAntoine V
5,1262424
answered Nov 15 '18 at 13:29
Antoine VAntoine V
5,1262424
5,1262424
add a comment |
add a comment |
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8
ScheduleDays?.Sum(w => w.WageCost) ?? 0;– SeM
Nov 15 '18 at 13:29
Write a check for null. SeM gave you the new null-conditional opeartor wich isa convencience feature that was added with C# 6 or so. But a good old
if(ScheduleDays == null) WageCost = 0;would also work.– Christopher
Nov 15 '18 at 13:30
@Christopher If I remember correctly, expression bodied properties was added in c#6. So I assumed he is using >=c#6.
– SeM
Nov 15 '18 at 13:34
@SeM: It is a solid asumption that anyone has access to those right now. I was just mentioning it for completeness.
– Christopher
Nov 15 '18 at 13:38