转自:
在写一个小程序的时候,碰到了这样的问题,需要用委托来挂接事件,但是又想在这事件中使用局部的变量,而委托一旦定义好后,挂接方就没有办法再添加额外的形参了。那有没有什么
办法,可以实现呢?
委托定义如下:
[csharp] view plaincopyprint?
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public class SocketSp
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{
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public delegate void ReceiveCompleted(byte[] receiveBuffer, int receiveTotalLen,Exception ex);
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public ReceiveCompleted receiveCompleted;
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}
挂接方定义如下
[csharp] view plaincopyprint?
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public class LinkOuter
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{
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SocketSp linkOuterSocket = new SocketSp();
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private void test(Socket requestHandleSocket)
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{
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}
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}
第一个想法是利用delegate,但是失败了。因为虽然挂接上去了,委托传进的参数丢了,无法进行后续操作。
[csharp] view plaincopyprint?
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private void test(Socket requestHandleSocket)
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{
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linkOuterSocket.receiveCompleted += delegate {
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};
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}
第二个想法是利用Action,结果也失败了。IDE提示委托Action未采用3个参数。
[csharp] view plaincopyprint?
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private void test(Socket requestHandleSocket)
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{
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linkOuterSocket.receiveCompleted += (Action)((outerReceiveBuffer, totalLen, ex) => {
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});
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}
第三个想法是利用lambda表达式,先与委托挂接,同时利用局部变量的调用,来实现参数传递到sendResponse函数中,以便后续操作。
[csharp] view plaincopyprint?
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private void test(Socket requestHandleSocket)
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{
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linkOuterSocket.receiveCompleted += new SocketSp.ReceiveCompleted((outerReceiveBuffer,totalLen,ex) =>
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{
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byte[] realOuterReceiveBuffer = new byte[totalLen];
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Array.Copy(outerReceiveBuffer, 0, realOuterReceiveBuffer, 0, totalLen);
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sendResponse(requestHandleSocket, realOuterReceiveBuffer,"200 OK", "text/html");
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});
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}
最终用lambda表达式实现了。
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