[英]What is the equivalent javascript closure in c#?
Consider this simple .js code: 考虑一下这个简单的.js代码:
const createCounter = () => {
let value = 0;
return {
increment: () => { value += 1 },
decrement: () => { value -= 1 },
logValue: () => { console.log(value); }
}
}
// Usage //用法
const { increment, decrement, logValue } = createCounter();
I'm pretty sure c# support first class function, note that I don't want to use classes to remake the code above. 我很确定c#支持第一类函数,请注意我不想使用类重新编写上面的代码。 What is the equivalent closure in c#? c#中的等价闭包是什么?
I have made this: 我做了这个:
public Func<WhatType?> CreateCounter = () => {
var value = 0;
return what?
}
You could use a mix of ValueTuples and lambda expressions . 您可以使用ValueTuples和lambda表达式的混合。
private static (Action increment, Action decrement, Action logValue) CreateCounter()
{
var value = 0;
return
(
() => value += 1,
() => value -= 1,
() => Console.WriteLine(value)
);
}
Usage 用法
var (increment, decrement, logValue) = CreateCounter();
increment();
increment();
decrement();
logValue();
Check out the following code using Dictionary
to Map enumerated data types
with an Action Delegate
使用Dictionary
来映射以下代码,使用Action Delegate
映射enumerated data types
void Main()
{
OperationActionDictionary[Operation.Increment](); // Execute Increment
OperationActionDictionary[Operation.Increment](); // Execute Increment
OperationActionDictionary[Operation.Decrement](); // Execute Decrement
OperationActionDictionary[Operation.LogValue](); // Execute LogValue
}
public enum Operation
{
Increment,
Decrement,
LogValue
}
public static int Value = 0;
public Dictionary<Operation,Action> OperationActionDictionary = new Dictionary<Operation, Action>
{
[Operation.Increment] = () => Value += 1,
[Operation.Decrement] = () => Value -= 1,
[Operation.LogValue] = () => Console.WriteLine($"Value :: {Value}")
};
Only catch here or in any other code for modifying a shared Value
object would be in case it is Multi thread access, then you need to take care of thread safety in this case using Interlocked.Increment
or Interlocked.Decrement
只有在这里或者用于修改共享Value
对象的任何其他代码时,如果它是多线程访问,那么在这种情况下你需要使用Interlocked.Increment
或Interlocked.Decrement
来处理线程安全。
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