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What is the use of ObservableCollection in .net?
...ed,
INotifyPropertyChanged
As such it is very useful when you want to know when the collection has changed. An event is triggered that will tell the user what entries have been added/removed or moved.
More importantly they are very useful when using databinding on a form.
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How to Implement Custom Table View Section Headers and Footers with Storyboard
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I know this question was for iOS 5, but for the benefit of future readers, note that effective iOS 6 we can now use dequeueReusableHeaderFooterViewWithIdentifier instead of dequeueReusableCellWithIdentifier.
So in viewDidLoad, ...
Visual Studio : short cut Key : Duplicate Line
...fter)
Ctrl + D
In Visual Studio 2017 (pre v15.6)
(edit) This feature is now built-in in VS2017: Ctrl + E, V duplicates a line if nothing is selected, or duplicates selection. You can assign it to a different key combination, or find it in the menu:
See this reference for more information.
Pre...
How do you create an asynchronous method in C#?
... build your own asynchronous methods to consume. So I have this code right now that consumes my method:
3 Answers
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Eclipse git checkout (aka, revert)
... not already show your repository, click on the project or file
You should now see the files you modified in the Unstaged Changes section
Double-click on the unstaged file
You now see a compare view with your version on the left and the version before the changes on the right
Now, to undo only som...
How to get 30 days prior to current date?
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Get next 30 days from today
let now = new Date()
console.log('Today: ' + now.toUTCString())
let next30days = new Date(now.setDate(now.getDate() + 30))
console.log('Next 30th day: ' + next30days.toUTCString())
Get last 30 days form today
let n...
Get timezone from DateTime
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DateTime itself contains no real timezone information. It may know if it's UTC or local, but not what local really means.
DateTimeOffset is somewhat better - that's basically a UTC time and an offset. However, that's still not really enough to determine the timezone, as many different t...
Why does the use of 'new' cause memory leaks?
I learned C# first, and now I'm starting with C++. As I understand, operator new in C++ is not similar to the one in C#.
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UINavigationBar custom back button without title
...evious view controller). The newly pushed view controller back button will now show whatever you put for initWithTitle, which in this case is an empty string.
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Many-to-many relationship with the same model in rails?
...column names are non-standard as well (not post_id), to prevent conflict.
Now in your model, you simply need to tell Rails about these couple of non-standard things. It will look as follows:
class Post < ActiveRecord::Base
has_and_belongs_to_many(:posts,
:join_table => "post_connection...