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Run a callback only if an attribute has changed in Rails
...
Rails 5.1+
class Page < ActiveRecord::Base
before_save :do_something, if: :will_save_change_to_status_id?
private
def do_something
# ...
end
end
The commit that changed ActiveRecord::Dirty is here: https://github.com/rails/rails/commit/16ae3db5a5c6a08383b974ae...
What are the differences between a multidimensional array and an array of arrays in C#?
...t32 'value') cil managed
{
// Code size 7 (0x7)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldarg.1
IL_0002: ldelem.ref
IL_0003: ldarg.2
IL_0004: ldarg.3
IL_0005: stelem.i4
IL_0006: ret
} // end of method Program::SetElementAt
.method private hidebysig static void SetElem...
AngularJS - Trigger when radio button is selected
...d many ng-xxxx kind of options but couldn't find the one..
I just want to call some function in the controller when radio button is selected.
...
C++特化模板函数的符号多重定义错误问题 - C/C++ - 清泛网 - 专注C/C++及内核技术
C++特化模板函数的符号多重定义错误问题error LNK2005: "void __stdcall SerializeElements<class CLogEvent> ...fatal error LNK1169: 找到一个或多个多重定义的符号.我...特化模板函数SerializeElements时，报重复定义的错误，如下：
error LNK2005: "void __std...
glob exclude pattern
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Really interesting solution! But my case is going to be extremely slow to make a read twice. Also if the content of a folder is big on an network directory, is going to be slow again. But in any case, really handy.
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What's the difference between ViewData and ViewBag?
...y typed view models (the same way as viewdata should be avoided).
So basically it replaces magic strings:
ViewData["Foo"]
with magic properties:
ViewBag.Foo
for which you have no compile time safety.
I continue to blame Microsoft for ever introducing this concept in MVC.
The name of the pro...
Can Objective-C switch on NSString?
... @abbood For more information about enum, see the posting NS_ENUM & NS_OPTIONS by Mattt Thompson.
– Basil Bourque
Oct 21 '13 at 21:32
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SQLAlchemy: how to filter date field?
...In fact, your query is right except for the typo: your filter is excluding all records: you should change the <= for >= and vice versa:
qry = DBSession.query(User).filter(
and_(User.birthday <= '1988-01-17', User.birthday >= '1985-01-17'))
# or same:
qry = DBSession.query(User)....
MongoDB not equal to
...b.inventory.find( { price: { $not: { $gt: 1.99 } } } )
That would select all documents where:
The price field value is less than or equal to 1.99 or the price
Field does not exist
share
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impro...
Reserved keywords in JavaScript
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Here is my poem, which includes all of the reserved keywords in JavaScript, and is dedicated to those who remain honest in the moment, and not just try to score:
Let this long package float,
Goto private class if short.
While protected with debugger case,...