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。
如果有Unix时间戳和ISO 8601格式的日期和时间就太好了。大量用于网站和休息服务。
我在我的Facebook图书馆里使用它。你可以找到源代码http://github.com/prabirshrestha/FacebookSharp/blob/master/src/FacebookSharp.Core/FacebookUtils/DateUtils.cs
private static readonly DateTime EPOCH = DateTime.SpecifyKind(new DateTime(1970, 1, 1, 0, 0, 0, 0),DateTimeKind.Utc);
public static DateTime FromUnixTimestamp(long timestamp)
{
return EPOCH.AddSeconds(timestamp);
}
public static long ToUnixTimestamp(DateTime date)
{
TimeSpan diff = date.ToUniversalTime() - EPOCH;
return (long)diff.TotalSeconds;
}
public static DateTime FromIso8601FormattedDateTime(string iso8601DateTime){
return DateTime.ParseExact(iso8601DateTime, "o", System.Globalization.CultureInfo.InvariantCulture);
}
public static string ToIso8601FormattedDateTime(DateTime dateTime)
{
return dateTime.ToString("o");
}
请随意在codeplex项目中使用。
下面是我用来减少提取单个属性的一些方法:
public static T GetAttribute<T>(this ICustomAttributeProvider provider, bool inherit = false, int index = 0) where T : Attribute
{
return provider.GetAttribute(typeof(T), inherit, index) as T;
}
public static Attribute GetAttribute(this ICustomAttributeProvider provider, Type type, bool inherit = false, int index = 0)
{
bool exists = provider.IsDefined(type, inherit);
if (!exists)
{
return null;
}
object[] attributes = provider.GetCustomAttributes(type, inherit);
if (attributes != null && attributes.Length != 0)
{
return attributes[index] as Attribute;
}
else
{
return null;
}
}
用法(枚举描述hack的实现):
public static string GetDescription(this Enum value)
{
var fieldInfo = value.GetType().GetField(value.ToString());
var attribute = fieldInfo.GetAttribute<DescriptionAttribute>();
return attribute != null ? attribute.Description : null;
}
请随意将其包含在CodePlex项目中!
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