в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

Admin: 1 версия

2010-05-26T12:19:56Z

1 версия

Новая страница

==Demonstrate multicasting==

<p>Create an invocation list, or chain, of methods that will be called when a delegate is invoked.</p>

<source lang="csharp">using System;

delegate string StrMod(ref string str);

class MultiCastDemo {
static string replaceSpaces(ref string a) {
Console.WriteLine("replaceSpaces");
return a;
}

static string removeSpaces(ref string a) {
Console.WriteLine("removeSpaces");
return a;
}

static string reverse(ref string a) {
Console.WriteLine("reverseSpaces");
return a;
}

public static void Main() {
StrMod strOp;
StrMod replaceSp = new StrMod(replaceSpaces);
StrMod removeSp = new StrMod(removeSpaces);
StrMod reverseStr = new StrMod(reverse);
string str = "This is a test";

// Set up multicast.
strOp = replaceSp;
strOp += reverseStr;

// Call multicast.
strOp(ref str);

// Remove replace and add remove.
strOp -= replaceSp;
strOp += removeSp;

str = "This is a test."; // reset string

// Call multicast.
strOp(ref str);
}
}</source>
<pre class=codeResult>replaceSpaces
reverseSpaces
reverseSpaces
removeSpaces</pre>

==Multicast delegates==

<source lang="csharp">using System;
class MainClass
{
delegate int MyDelegate(string s);
static void Main(string[] args)
{
string MyString = "Hello World";

MyDelegate Multicast = null;
Multicast += new MyDelegate(DoSomething);
Multicast += new MyDelegate(DoSomething2);
Multicast(MyString);
}
static int DoSomething(string s)
{
Console.WriteLine("DoSomething");

return 0;
}
static int DoSomething2(string s)
{
Console.WriteLine("DoSomething2");
return 0;
}
}</source>
<pre class=codeResult>DoSomething
DoSomething2</pre>

==Remove delegate from Multicast==

<source lang="csharp">using System;
class MainClass
{
delegate int MyDelegate(string s);
static void Main(string[] args)
{
string MyString = "Hello World";
//Or you can Multicast delegates by doing this
MyDelegate Multicast = null;
Multicast += new MyDelegate(DoSomething);
Multicast += new MyDelegate(DoSomething2);
Multicast -= new MyDelegate(DoSomething2);

Multicast(MyString);
}
static int DoSomething(string s)
{
Console.WriteLine("DoSomething");

return 0;
}
static int DoSomething2(string s)
{
Console.WriteLine("DoSomething2");
return 0;
}
}</source>
<pre class=codeResult>DoSomething</pre>

==uses the reference parameter of a multicast delegate as a counter==

<source lang="csharp">using System;
public delegate void DelegateClass(int valCount, ref int refCount);
public class Counter {
public static void Main() {
DelegateClass del = (DelegateClass)AddOne + (DelegateClass)AddTwo + (DelegateClass)AddOne;
int valCount = 0;
int refCount = 0;
del(valCount, ref refCount);
Console.WriteLine("Value count = {0}", valCount); // 0
Console.WriteLine("Reference count = {0}",refCount); // 4
}
public static void AddOne(int valCount,ref int refCount) {
++valCount;
++refCount;
}
public static void AddTwo(int valCount,ref int refCount) {
valCount += 2;
refCount += 2;
}
}</source>

← Предыдущая	Версия 15:31, 26 мая 2010
(нет различий)

Csharp/CSharp Tutorial/delegate/Multi cast delegate - История изменений

в 15:31, 26 мая 2010

Admin: 1 версия