让我们把你的优秀和最喜欢的扩展方法列一个列表。
要求是必须发布完整的代码,以及如何使用它的示例和解释。
基于对这个主题的高度兴趣,我在Codeplex上建立了一个名为extensionoverflow的开源项目。
请将您的回答标记为接受,以便将代码放入Codeplex项目。
请张贴完整的源代码,而不是一个链接。
Codeplex上新闻:
24.08.2010 Codeplex页面现在在这里:http://extensionoverflow.codeplex.com/
11.11.2008 XmlSerialize / XmlDeserialize现在是实现和单元测试。
11.11.2008仍有发展空间。;-)现在就加入!
11.11.2008第三位贡献者加入了ExtensionOverflow,欢迎加入BKristensen
11.11.2008 FormatWith现在是实现和单元测试。
09.11.2008第二个贡献者加入ExtensionOverflow。欢迎来到chakrit。
我们需要更多的开发人员。: -)
09.11.2008 ThrowIfArgumentIsNull现已在Codeplex上实现和单元测试。
这些扩展方法异步调用事件。他们受到了StackOverflow的启发。
/// <summary>
/// Invoke an event asynchronously. Each subscriber to the event will be invoked on a separate thread.
/// </summary>
/// <param name="someEvent">The event to be invoked asynchronously.</param>
/// <param name="sender">The sender of the event.</param>
/// <param name="args">The args of the event.</param>
/// <typeparam name="TEventArgs">The type of <see cref="EventArgs"/> to be used with the event.</typeparam>
public static void InvokeAsync<TEventArgs>(this EventHandler<TEventArgs> someEvent, object sender, TEventArgs args)
where TEventArgs : EventArgs
{
if (someEvent == null)
{
return;
}
var eventListeners = someEvent.GetInvocationList();
AsyncCallback endAsyncCallback = delegate(IAsyncResult iar)
{
var ar = iar as AsyncResult;
if (ar == null)
{
return;
}
var invokedMethod = ar.AsyncDelegate as EventHandler<TEventArgs>;
if (invokedMethod != null)
{
invokedMethod.EndInvoke(iar);
}
};
foreach (EventHandler<TEventArgs> methodToInvoke in eventListeners)
{
methodToInvoke.BeginInvoke(sender, args, endAsyncCallback, null);
}
}
/// <summary>
/// Invoke an event asynchronously. Each subscriber to the event will be invoked on a separate thread.
/// </summary>
/// <param name="someEvent">The event to be invoked asynchronously.</param>
/// <param name="sender">The sender of the event.</param>
/// <param name="args">The args of the event.</param>
public static void InvokeAsync(this EventHandler someEvent, object sender, EventArgs args)
{
if (someEvent == null)
{
return;
}
var eventListeners = someEvent.GetInvocationList();
AsyncCallback endAsyncCallback = delegate(IAsyncResult iar)
{
var ar = iar as AsyncResult;
if (ar == null)
{
return;
}
var invokedMethod = ar.AsyncDelegate as EventHandler;
if (invokedMethod != null)
{
invokedMethod.EndInvoke(iar);
}
};
foreach (EventHandler methodToInvoke in eventListeners)
{
methodToInvoke.BeginInvoke(sender, args, endAsyncCallback, null);
}
}
使用方法:
public class Foo
{
public event EventHandler<EventArgs> Bar;
public void OnBar()
{
Bar.InvokeAsync(this, EventArgs.Empty);
}
}
请注意,在调用事件之前,您不必检查事件是否为空。例如:
EventHandler<EventArgs> handler = Bar;
if (handler != null)
{
// Invoke the event
}
测试:
void Main()
{
EventHandler<EventArgs> handler1 =
delegate(object sender, EventArgs args)
{
// Simulate performing work in handler1
Thread.Sleep(100);
Console.WriteLine("Handled 1");
};
EventHandler<EventArgs> handler2 =
delegate(object sender, EventArgs args)
{
// Simulate performing work in handler2
Thread.Sleep(50);
Console.WriteLine("Handled 2");
};
EventHandler<EventArgs> handler3 =
delegate(object sender, EventArgs args)
{
// Simulate performing work in handler3
Thread.Sleep(25);
Console.WriteLine("Handled 3");
};
var foo = new Foo();
foo.Bar += handler1;
foo.Bar += handler2;
foo.Bar += handler3;
foo.OnBar();
Console.WriteLine("Start executing important stuff");
// Simulate performing some important stuff here, where we don't want to
// wait around for the event handlers to finish executing
Thread.Sleep(1000);
Console.WriteLine("Finished executing important stuff");
}
调用事件将(通常)产生以下输出:
开始执行重要的事情
处理3
处理2
处理1
完成重要的任务
如果事件是同步调用的,它总是会产生这样的输出-并延迟“重要”内容的执行:
处理1
处理2
处理3
开始执行重要的事情
完成重要的任务
我最喜欢的是字符串上的IsLike()扩展。IsLike()匹配VB的Like操作符,当你不想写一个完整的正则表达式来解决你的问题时,它很方便。用法是这样的:
"abc".IsLike("a*"); // true
"Abc".IsLike("[A-Z][a-z][a-z]"); // true
"abc123".IsLike("*###"); // true
"hat".IsLike("?at"); // true
"joe".IsLike("[!aeiou]*"); // true
"joe".IsLike("?at"); // false
"joe".IsLike("[A-Z][a-z][a-z]"); // false
下面是代码
public static class StringEntentions {
/// <summary>
/// Indicates whether the current string matches the supplied wildcard pattern. Behaves the same
/// as VB's "Like" Operator.
/// </summary>
/// <param name="s">The string instance where the extension method is called</param>
/// <param name="wildcardPattern">The wildcard pattern to match. Syntax matches VB's Like operator.</param>
/// <returns>true if the string matches the supplied pattern, false otherwise.</returns>
/// <remarks>See http://msdn.microsoft.com/en-us/library/swf8kaxw(v=VS.100).aspx</remarks>
public static bool IsLike(this string s, string wildcardPattern) {
if (s == null || String.IsNullOrEmpty(wildcardPattern)) return false;
// turn into regex pattern, and match the whole string with ^$
var regexPattern = "^" + Regex.Escape(wildcardPattern) + "$";
// add support for ?, #, *, [], and [!]
regexPattern = regexPattern.Replace(@"\[!", "[^")
.Replace(@"\[", "[")
.Replace(@"\]", "]")
.Replace(@"\?", ".")
.Replace(@"\*", ".*")
.Replace(@"\#", @"\d");
var result = false;
try {
result = Regex.IsMatch(s, regexPattern);
}
catch (ArgumentException ex) {
throw new ArgumentException(String.Format("Invalid pattern: {0}", wildcardPattern), ex);
}
return result;
}
}
c#中Smalltalk样式的if/else。
您可以自由地在codeplex上使用您使用的任何许可证
using System;
namespace SmalltalkBooleanExtensionMethods
{
public static class BooleanExtension
{
public static T ifTrue<T> (this bool aBoolean, Func<T> method)
{
if (aBoolean)
return (T)method();
else
return default(T);
}
public static void ifTrue (this bool aBoolean, Action method)
{
if (aBoolean)
method();
}
public static T ifFalse<T> (this bool aBoolean, Func<T> method)
{
if (!aBoolean)
return (T)method();
else
return default(T);
}
public static void ifFalse (this bool aBoolean, Action method)
{
if (!aBoolean)
method();
}
public static T ifTrueifFalse<T> (this Boolean aBoolean, Func<T> methodA, Func<T> methodB)
{
if (aBoolean)
return (T)methodA();
else
return (T)methodB();
}
public static void ifTrueifFalse (this Boolean aBoolean, Action methodA, Action methodB)
{
if (aBoolean)
methodA();
else
methodB();
}
}
}
你可能已经有了一个timesRepeat方法。
using System;
namespace SmalltalkBooleanExtensionMethods
{
public static class IntExtension
{
public static int timesRepeat<T>(this int x, Func<T> method)
{
for (int i = x; i > 0; i--)
{
method();
}
return x;
}
public static int timesRepeat(this int x, Action method)
{
for (int i = x; i > 0; i--)
{
method();
}
return x;
}
}
}
Nunit测试
using System;
using SmalltalkBooleanExtensionMethods;
using NUnit.Framework;
namespace SmalltalkBooleanExtensionMethodsTest
{
[TestFixture]
public class SBEMTest
{
int i;
bool itWorks;
[SetUp]
public void Init()
{
i = 0;
itWorks = false;
}
[Test()]
public void TestifTrue()
{
itWorks = (true.ifTrue(() => true));
Assert.IsTrue(itWorks);
}
[Test()]
public void TestifFalse()
{
itWorks = (false.ifFalse(() => true));
Assert.IsTrue(itWorks);
}
[Test()]
public void TestifTrueifFalse()
{
itWorks = false.ifTrueifFalse(() => false, () => true);
Assert.IsTrue(itWorks);
itWorks = false;
itWorks = true.ifTrueifFalse(() => true, () => false);
Assert.IsTrue(itWorks);
}
[Test()]
public void TestTimesRepeat()
{
(5).timesRepeat(() => i = i + 1);
Assert.AreEqual(i, 5);
}
[Test()]
public void TestVoidMethodIfTrue()
{
true.ifTrue(() => SetItWorksBooleanToTrue());
Assert.IsTrue(itWorks);
}
[Test()]
public void TestVoidMethodIfFalse()
{
false.ifFalse(() => SetItWorksBooleanToTrue());
Assert.IsTrue(itWorks);
}
public void TestVoidMethodIfTrueIfFalse()
{
true.ifTrueifFalse(() => SetItWorksBooleanToTrue(), () => SetItWorksBooleanToFalse());
false.ifTrueifFalse(() => SetItWorksBooleanToFalse(), () => SetItWorksBooleanToTrue());
Assert.IsTrue(itWorks);
}
public void TestVoidMethodTimesRepeat()
{
(5).timesRepeat(() => AddOneToi());
Assert.AreEqual(i, 5);
}
public void SetItWorksBooleanToTrue()
{
itWorks = true;
}
public void SetItWorksBooleanToFalse()
{
itWorks = false;
}
public void AddOneToi()
{
i = i + 1;
}
}
}