[英]Storing a method as a member variable of a class
I have this as one of my members of the class 'KeyEvent': 我把它作为我的'KeyEvent'类的成员之一:
private delegate void eventmethod();
And the constructor: 和构造函数:
public KeyEvent(eventmethod D)
{
D();
}
What I want to do is instead of calling D() there, I want to store that method (D) as a member variable of KeyEvent, so something like: 我想要做的不是在那里调用D(),我想将该方法(D)存储为KeyEvent的成员变量,所以类似于:
stored_method = D();
And then later in another method of KeyEvent, do something like: 然后在另一个KeyEvent方法中,执行以下操作:
stored_method();
How can I do this? 我怎样才能做到这一点?
You pretty much have the code already. 你已经拥有了很多代码。 Just create a member field of the right delegate type and save the parameter to it just like you would with any other data type.
只需创建一个右代理类型的成员字段,并将参数保存到它,就像使用任何其他数据类型一样。
private eventmethod MySavedEvent;
public void KeyEvent(eventmethod D) {
// Save the delegate
MySavedEvent = D;
}
public void CallSavedEvent() {
if (MySavedEvent != null) {
MySavedEvent();
}
}
You could do something like: 你可以这样做:
private Action CallBackFunction {get; set;}
public KeyEvent(Action callback) {
CallBackFunction = callback;
}
Which can be instantiated by: 哪个可以通过以下方式实例化:
new KeyEvent(MyFunction);
Where MyFunction is the name of some function in that class 其中MyFunction是该类中某些函数的名称
The KeyEvent class can then invoke that function with: 然后,KeyEvent类可以使用以下命令调用该函数:
CallBackFunction();
The Action class also allows strongly typed parameters to be passed in and the Func class can be used for methods that return a result. Action类还允许传入强类型参数,Func类可用于返回结果的方法。
the thing that you want is called "first class function" http://en.wikipedia.org/wiki/First-class_function 你想要的东西叫做“头等功能” http://en.wikipedia.org/wiki/First-class_function
C#, since version 3, supports anonymous functions and lambda expressions. 从版本3开始,C#支持匿名函数和lambda表达式。
So you can use Func<A,R>
which represents a function taking an argument of type A and returning a value of type R 因此,您可以使用
Func<A,R>
表示采用类型A的参数并返回类型R的值的函数
from wiki 来自维基
static Func<double, double> MakeDerivative(Func<double, double> f, double deltaX)
{
return (x) => (f(x + deltaX) - f(x - deltaX)) / (2 * deltaX);
}
public class KeyEvent
{
private eventmethod hurr;
public KeyEvent(eventmethod D)
{
hurr = D;
}
public void SomeOtherMethod()
{
hurr();
}
}
Couple things... PascalCase types/delegates/etc (EventMethod) and camelCase arguments (d, dIsMyMethod). 几件事...... PascalCase类型/委托/ etc(EventMethod)和camelCase参数(d,dIsMyMethod)。 And reuse what the framework gives you:
private Action hurr;
并重用框架为您提供的内容:
private Action hurr;
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