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Can a C# class inherit attributes from its interface?
...h is searched for the attributes.</param>
/// <returns>Returns all attributes.</returns>
public static T[] GetCustomAttributes<T>( this Type type ) where T : Attribute
{
return GetCustomAttributes( type, typeof( T ), false ).Select( arg => (T)arg ).ToArray();
}
/// <...
Rails hidden field undefined method 'merge' error
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You should do:
<%= f.hidden_field :service, :value => "test" %>
hidden_field expects a hash as a second argument
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How to find Unused Amazon EC2 Security groups
...AWS CLI tool, I found an easy way to get what I need:
First, get a list of all security groups
aws ec2 describe-security-groups --query 'SecurityGroups[*].GroupId' --output text | tr '\t' '\n'
Then get all security groups tied to an instance, then piped to sort then uniq:
aws ec2 describe-instance...
How to access component methods from “outside” in ReactJS?
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class Parent extends React.Class {
constructor(props) {
this._child = React.createRef();
}
componentDidMount() {
console.log(this._child.current.someMethod()); // Prints 'bar'
}
render() {
return (
<div>
<Child ref=...
How can I set the request header for curl?
...;q=0.8,en;q=0.6' \
-e localhost \
-A 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.65 Safari/537.36' \
'http://restapi.some-site.com/getsomething?argument=value&argument2=value'
In this example the referer (-e or --referer in curl) is '...
“Variable” variables in Javascript?
...usly consider that). It is possible to access some global variables dynamically via window, but that doesn't work for variables local to a function. Global variables that do not become a property of window are variables defined with let and const, and classes.
There is almost always a better soluti...
rails 3 validation on uniqueness on multiple attributes
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In Rails 2, I would have written:
validates_uniqueness_of :zipcode, :scope => :recorded_at
In Rails 3:
validates :zipcode, :uniqueness => {:scope => :recorded_at}
For multiple attributes:
validates :zipcode, :uniqueness => {:scope => [:recorded_at...
What are the differences between struct and class in C++?
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That's not really a second difference, it's just that the question stated the difference incompletely. All subobjects are private by default when using the class, public by default with struct, and both define a class type.
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LINQ: Distinct values
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Oh so by "larger type" you may mean I still want all properties in the result even though I only want to compare a few properties to determine distinctness?
– The Red Pea
Sep 20 '16 at 14:31
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Getting an “ambiguous redirect” error
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Bash can be pretty obtuse sometimes.
The following commands all return different error messages for basically the same error:
$ echo hello >
bash: syntax error near unexpected token `newline`
$ echo hello > ${NONEXISTENT}
bash: ${NONEXISTENT}: ambiguous redirect
$ echo hello ...