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The cast to value type 'Int32' failed because the materialized value is null
...
where u.ID == userID
select (int?)ch.Amount).Sum() ?? 0;
This first casts to int? to tell the C# compiler that this expression can indeed return null, even though Sum() returns an int. Then we use the normal ?? operator to handle the null case....
Can you give a Django app a verbose name for use throughout the admin?
...h to the appropriate AppConfig subclass to be configured explicitly in INSTALLED_APPS.
Example:
INSTALLED_APPS = [
# ...snip...
'yourapp.apps.YourAppConfig',
]
Then alter your AppConfig as listed below.
Django 1.7
As stated by rhunwicks' comment to OP, this is now possible out of the ...
How to determine the version of the C++ standard used by the compiler?
...
By my knowledge there is no overall way to do this. If you look at the headers of cross platform/multiple compiler supporting libraries you'll always find a lot of defines that use compiler specific constructs to determine such things:
/*Define Microsoft V...
split string only on first instance of specified character
...Very elegant. Works like a charm. Thank you.
– Ofeargall
Jan 5 '11 at 18:43
12
Just to be clear, ...
How to compare type of an object in Python?
Basically I want to do this:
14 Answers
14
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Abstract classes in Swift Language
... importantly, notice that there is no dynamic dispatch. When logSalary is called on the instance that is stored as a SoftwareEngineer it calls the overridden version of the method. When logSalary is called on the instance after it has been cast to an Employee, it calls the original implementation (i...
How can I use jQuery to make an input readonly?
...illa.org/en-US/docs/Web/HTML/Attributes/readonly). I attempted to create a select that would allow the options to be shown, but not an other option to be selected. This cannot be done with readonly.
– R. Schreurs
Sep 10 at 18:59
...
Parse JSON String into a Particular Object Prototype in JavaScript
...olution below that applies Object.assign(..) recursively that can automatically resolve properties (with a bit of information provided in advance)
– vir us
Dec 8 '17 at 16:13
...
What __init__ and self do on Python?
...to declare it explicitly. When you create an instance of the A class and call its methods, it will be passed automatically, as in ...
a = A() # We do not pass any argument to the __init__ method
a.method_a('Sailor!') # We only pass a single argument
The __init__ method is roughly w...
difference between Product Backlog Item and Feature in Team Foundation work item types
...n I want to create a new work item, I'm given a list of work item types to select from, among which are "Product Backlog Item" and "Feature".
...