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C# pattern to prevent an event handler hooked twice [duplicate]
...Linq; // Required for the .Contains call below:
...
private EventHandler foo;
public event EventHandler Foo
{
add
{
if (foo == null || !foo.GetInvocationList().Contains(value))
{
foo += value;
}
}
remove
{
foo -= value;
}
}
Usin...
What is this crazy C++11 syntax ==> struct : bar {} foo {};?
...First, we'll take a bog-standard abstract UDT (User-Defined Type):
struct foo { virtual void f() = 0; }; // normal abstract type
foo obj;
// error: cannot declare variable 'obj' to be of abstract type 'foo'
Let's also recall that we can instantiate the UDT at the same time that we define it:
str...
Which is preferred: Nullable.HasValue or Nullable != null?
...nd to always use !=null
And this is why:
Let imagine we have some class Foo with a nullable double variable SomeDouble
public class Foo
{
public double? SomeDouble;
//some other properties
}
If somewhere in our code we want to get all Foo with a non null SomeDouble values from a col...
Twig ternary operator, Shorthand if-then-else
...
You can use shorthand syntax as of Twig 1.12.0
{{ foo ?: 'no' }} is the same as {{ foo ? foo : 'no' }}
{{ foo ? 'yes' }} is the same as {{ foo ? 'yes' : '' }}
share
|
impro...
AngularJS: ng-show / ng-hide not working with `{{ }}` interpolation
...
The foo.bar reference should not contain the braces:
<p ng-hide="foo.bar">I could be shown, or I could be hidden</p>
<p ng-show="foo.bar">I could be shown, or I could be hidden</p>
Angular expressions n...
How do I import other TypeScript files?
...ry.d.ts"/>
/// <reference path="components/someclass.ts"/>
class Foo { }
etc.
These paths are relative to the current file.
Your example:
/// <reference path="moo.ts"/>
class bar extends moo.foo
{
}
sh...
how to “reimport” module to python then code be changed after import
I have a foo.py
4 Answers
4
...
How do I perform a Perl substitution on a string while keeping the original?
...a string without changing the original:
(my $newstring = $oldstring) =~ s/foo/bar/g;
In perl 5.14.0 or later, you can use the new /r non-destructive substitution modifier:
my $newstring = $oldstring =~ s/foo/bar/gr;
Note: The above solutions work without g too. They also work with any other...
Why do you need to invoke an anonymous function on the same line?
...e is your basic declared function.
Ex. 1:
var message = 'SO';
function foo(msg) {
alert(msg);
}
foo(message);
Functions are objects, and can be grouped. So let's throw parens around the function.
Ex. 2:
var message = 'SO';
function foo(msg) { //declares foo
alert(msg);
}
(foo)(m...
Can Python test the membership of multiple values in a list?
...ant, and will work in nearly all cases:
>>> all(x in ['b', 'a', 'foo', 'bar'] for x in ['a', 'b'])
True
The expression 'a','b' in ['b', 'a', 'foo', 'bar'] doesn't work as expected because Python interprets it as a tuple:
>>> 'a', 'b'
('a', 'b')
>>> 'a', 5 + 2
('a', 7)
...