blocks|key|1666217|text|下面是一个很好的例子，请看一下如何使用委托|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1666218|Delegate+Example|offset|length|1666219|为什么要使用反射？还会有不同数量的参数吗？或者您知道方法信号将保持不变(还要记住C#支持params[]关键字)|1666220|params+c#|1666221|HTH|1666222|骨骼|1666223|entityMap|0|LINK|mutability|MUTABLE|url|http://www.c-sharpcorner.com/UploadFile/Ashush/Delegates02152008155757PM/Delegates.aspx|1|http://msdn.microsoft.com/en-us/library/w5zay9db(VS.71).aspx^0|0|0|G|0|0|0|0|9|1|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Y|8|@]|9|@$D|Z|E|10|1|11]]|A|$]]|$1|F|3|G|5|6|7|12|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|13|8|@]|9|@$D|14|E|15|1|16]]|A|$]]|$1|J|3|K|5|6|7|17|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|18|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|O|$P|$5|Q|R|S|A|$T|U]]|V|$5|Q|R|S|A|$T|W]]]]

please have a look at using delegates here is a great example

<a href="http://www.c-sharpcorner.com/UploadFile/Ashush/Delegates02152008155757PM/Delegates.aspx" rel="nofollow noreferrer">Delegate Example</a>

why are you using reflection? will there ever be a different number of params? or do you know the method signture will remain constant (also remember C# supports the params[] keyword)

<a href="http://msdn.microsoft.com/en-us/library/w5zay9db(VS.71).aspx" rel="nofollow noreferrer">params c#</a>

HTH

Bones

blocks|key|1666285|text|你应该先有一个委托|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1666286|delegate+int+Operation(int+a,+int+b)|code-block|syntax|javascript|1666287|然后它变成了：|1666288|public+void+InvokeMethod(Operation+method,+object+target,+object+param)
{
++++method((int)+target,+(int)+param);
}|1666289|不需要调用任何调用。|1666290|和dbone一样，我不确定为什么你需要一个params[]数组。您能说明一下params的扩展用途吗？|1666291|此外，我还必须更正您的问题中的某些内容，因为这将导致编译错误:p|1666292|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

You should have a delegate first

<pre><code>delegate int Operation(int a, int b)
</code></pre>

then it becomes:

<pre><code>public void InvokeMethod(Operation method, object target, object param)
{
 method((int) target, (int) param);
}
</code></pre>

No need for any call to Invoke.

As with dbone I'm unsure why you would need a params[] array. Would you clarify the expanded usage for the params?

Also, I'll have to correct something in your question though, because it will cause a compilation error :p

blocks|key|1451325|text|这样的东西对你来说应该是有效的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1451326|delegate+int+MyDelegate(int+a,+int+b);
public+int+Add(int+a,+int+b)+{
++++return+a+%2B+b;
}
public+void+InvokeMethod(Delegate+method,+object[]+param)+{
++++Console.WriteLine(method.DynamicInvoke(param));
}
public+Form1()+{+++++++
++++InitializeComponent();
++++InvokeMethod(new+MyDelegate(Add),+new+object[]+{+1,+2+});
}|code-block|syntax|javascript|1451327|祝好运!|1451328|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Something like this ought to work for you:

<pre><code>delegate int MyDelegate(int a, int b);
public int Add(int a, int b) {
 return a + b;
}
public void InvokeMethod(Delegate method, object[] param) {
 Console.WriteLine(method.DynamicInvoke(param));
}
public Form1() { 
 InitializeComponent();
 InvokeMethod(new MyDelegate(Add), new object[] { 1, 2 });
}
</code></pre>

Good luck!

blocks|key|1666348|text|我想你想要的是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1666349|static+object+InvokeMethod(Delegate+method,+params+object[]+args){
++++return+method.DynamicInvoke(args);
}

static+int+Add(int+a,+int+b){
++++return+a+%2B+b;
}

static+void+Test(){
++++Console.WriteLine(InvokeMethod(new+Func<int,+int,+int>(Add),+5,+4));
}|code-block|syntax|javascript|1666350|打印"9“。|1666351|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I think what you want is:

<pre><code>static object InvokeMethod(Delegate method, params object[] args){
 return method.DynamicInvoke(args);
}

static int Add(int a, int b){
 return a + b;
}

static void Test(){
 Console.WriteLine(InvokeMethod(new Func&lt;int, int, int&gt;(Add), 5, 4));
}
</code></pre>

Prints "9".

blocks|key|1451432|text|将方法组、匿名方法或lambda表达式转换为委托需要编译器知道确切的委托类型。但是，您可以使用lambda表达式和捕获的变量来简化此操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1451433|public+void+InvokeMethod(Action+action)
{
++++action();
}

public+int+Add(int+a,+int+b)
{
++++return+a+%2B+b;
}

public+void+Test()
{++++
++++InvokeMethod(()+=>+Add(2,+3));
}|code-block|syntax|javascript|1451434|这基本上会以正常的方式延迟调用，但会将对Add的实际调用包装在一个普通的Action委托中。|offset|length|style|CODE|1451435|如果这不能满足您的要求，也许您可以告诉我们更多关于您真正想要实现的目标。|1451436|编辑:如果这是生成的代码，您可以使用正确的类型参数强制转换为Func<...>+-假设类型参数不太多。除此之外，没有真正的方法来传入一个方法组。偶尔会有人要求"infoof(...)“运算符(类似于typeof，但用于成员)，它会给你一个MemberInfo，但它实际上并不存在。|1451437|entityMap^0|0|0|K|3|10|6|0|0|U|9|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]|$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|10|8|@$I|11|J|12|K|L]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|R|$]]

Converting a method group, anonymous method or lambda expression to a delegate requires the compiler to know the exact delegate type. However, you could potentially use lambda expressions and captured variables to make this simpler:

<pre><code>public void InvokeMethod(Action action)
{
 action();
}

public int Add(int a, int b)
{
 return a + b;
}

public void Test()
{ 
 InvokeMethod(() =&gt; Add(2, 3));
}
</code></pre>

That basically delays invocation in the normal way, but by wrapping the actual call to <code>Add</code> in a plain <code>Action</code> delegate.

If that doesn't fulfil your requirements, perhaps you can tell us a bit more about what you're really trying to achieve.

EDIT: If this is generated code, you can cast to a <code>Func&lt;...&gt;</code> with the right type arguments - assuming there aren't too many. Other than that, there's no real way of just passing in a method group. There's been occasional calls for an "infoof(...)" operator (like typeof but for members) which would give you a MemberInfo, but that doesn't actually exist.

blocks|key|1451471|text|看看Justin+Etheredge写的Functional+Programming+Series。你应该在那里找到你的问题的解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1451472|entityMap|0|LINK|mutability|MUTABLE|url|http://web.archive.org/web/20110720022241/https://www.codethinked.com/category/functional-programming-series^0|K|T|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Look at <a href="http://web.archive.org/web/20110720022241/https://www.codethinked.com/category/functional-programming-series" rel="nofollow noreferrer">Functional Programming Series</a> by Justin Etheredge.
You should find solution to your problem there.

blocks|key|1451581|text|例如，如果您需要将方法作为参数传递，以及需要捕获返回值以进行进一步处理。那么上面的例子就可以很好地工作了。但是，假设您需要传递一个具有空返回类型的方法，那么您需要创建另一个版本的InvokeMethod函数。检查下面的示例。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1451582|private+static+T+retry<T>(Delegate+method,+params+object[]+args)
{
++++for+(int+i+=+0;+i+<=+3;+i%2B%2B)
++++{
++++++++try
++++++++{
++++++++++++return+(T)method.DynamicInvoke(args);
++++++++}
++++++++catch+(Exception+ex)
++++++++{
++++++++++++if+(i+==+3)
++++++++++++{
++++++++++++++++logMessage(ex.Message);
++++++++++++}
++++++++++++Console.WriteLine("Retry+count+"+%2B+i);
++++++++++++Thread.Sleep(10);
++++++++}
++++}
++++return+default(T);
}

private+static+void+retry2(Delegate+method,+params+object[]+args)
{
++++for+(int+i+=+0;+i+<=+3;+i%2B%2B)
++++{
++++++++try
++++++++{
++++++++++++method.DynamicInvoke(args);
++++++++++++break;
++++++++}
++++++++catch+(Exception+ex)
++++++++{
++++++++++++if+(i+==+3)
++++++++++++{
++++++++++++++++logMessage(ex.Message);
++++++++++++++++//return+default(T);
++++++++++++}
++++++++++++Console.WriteLine("Retry+count+"+%2B+i);
++++++++++++Thread.Sleep(10);
++++++++}
++++}
}
static+bool+isSuccess+=+true;
static+void+logMessage(string+msg)
{
++++isSuccess+=+false;
++++Console.WriteLine(msg);
}

static+int+Add(int+a,+int+b)
{
++++return+a+%2B+b;
}

static+void+Add2(int+a,+int+b)
{
++++int+c+=+a+%2B+b;
++++Console.WriteLine(c);
}

static+void+Main(string[]+args)
{
++++int+d+=+retry<int>(new+Func<int,+int,+int>(Add),+6,+7.7);
++++Console.Write("++"+%2B+d+%2B+"\n"%2BisSuccess);

++++retry2(new+Action<int,+int>(Add2),+45,+60);

++++Console.ReadKey();
}|code-block|syntax|javascript|1451583|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Say If you need to pass the method as parameter as well as you need to catch the return value for further processing . Then the above examples will work fine . 
But say if you need to pass a method with void return type then you need to create one more version of the InvokeMethod function.
Check the example below.

<pre><code>private static T retry&lt;T&gt;(Delegate method, params object[] args)
{
 for (int i = 0; i &lt;= 3; i++)
 {
 try
 {
 return (T)method.DynamicInvoke(args);
 }
 catch (Exception ex)
 {
 if (i == 3)
 {
 logMessage(ex.Message);
 }
 Console.WriteLine("Retry count " + i);
 Thread.Sleep(10);
 }
 }
 return default(T);
}

private static void retry2(Delegate method, params object[] args)
{
 for (int i = 0; i &lt;= 3; i++)
 {
 try
 {
 method.DynamicInvoke(args);
 break;
 }
 catch (Exception ex)
 {
 if (i == 3)
 {
 logMessage(ex.Message);
 //return default(T);
 }
 Console.WriteLine("Retry count " + i);
 Thread.Sleep(10);
 }
 }
}
static bool isSuccess = true;
static void logMessage(string msg)
{
 isSuccess = false;
 Console.WriteLine(msg);
}

static int Add(int a, int b)
{
 return a + b;
}

static void Add2(int a, int b)
{
 int c = a + b;
 Console.WriteLine(c);
}

static void Main(string[] args)
{
 int d = retry&lt;int&gt;(new Func&lt;int, int, int&gt;(Add), 6, 7.7);
 Console.Write(" " + d + "\n"+isSuccess);

 retry2(new Action&lt;int, int&gt;(Add2), 45, 60);

 Console.ReadKey();
}
</code></pre>

Is it possible to pass a function as a parameter in C#? I can do it using the Func or Action classes, but this forces me to declare the entire function signature at once. When I try to use Delegate, I get a compile error saying it can't convert a method group to a Delegate. 

I'm working on <a href="http://www.codeplex.com/axial" rel="noreferrer">Axial</a> and I'm trying to allow users to call web services. What I'm going for is the ability to create the Visual Studio proxy class and then pass in the generated function. The function signature doesn't matter because the generated code only uses the function name. However, I'd like to pass in the function instead of the name for two reasons: the ability to use the proxy's Url property and a compiler error if the web service doesn't exist or is updated in Visual Studio.

<pre><code>
public void AlertIt(object o) {
 Axial.DOM.Window.Alert(o.ToString());
}
public void CallAddService() {
 object[] param = new object[] { int.Parse(txtA.Text), int.Parse(txtB.Text) };
 Axial.ServerScript.CallWebService(new WSProxy.WS().Add, param, AlertIt, AlertIt);
}

class Axial.ServerScript {
 public void CallWebService(Delegate method, object[] param, Action&lt;object&gt; successCallback, Action&lt;object&gt; failureCallback) {
 // translate to javascript (already working)
 }
}
</code></pre>

How to pass a function as a parameter in C#?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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在C#中可以将函数作为参数传递吗？我可以使用Func或Action类来实现，但这迫使我一次声明整个函数签名。当我尝试使用Delegate时，我得到一个编译错误，说它不能将一个方法组转换成一个Delegate。我正在开发，并尝试允许用户调用web服务。我想要的是能够创建Visual Studio代理类，然后传入生成的函数...

问如何在C#中将函数作为参数传递？
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