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。
public static bool In<T>(this T source, params T[] list)
{
if(null==source) throw new ArgumentNullException("source");
return list.Contains(source);
}
允许我替换:
if(reallyLongIntegerVariableName == 1 ||
reallyLongIntegerVariableName == 6 ||
reallyLongIntegerVariableName == 9 ||
reallyLongIntegerVariableName == 11)
{
// do something....
}
and
if(reallyLongStringVariableName == "string1" ||
reallyLongStringVariableName == "string2" ||
reallyLongStringVariableName == "string3")
{
// do something....
}
and
if(reallyLongMethodParameterName == SomeEnum.Value1 ||
reallyLongMethodParameterName == SomeEnum.Value2 ||
reallyLongMethodParameterName == SomeEnum.Value3 ||
reallyLongMethodParameterName == SomeEnum.Value4)
{
// do something....
}
:
if(reallyLongIntegerVariableName.In(1,6,9,11))
{
// do something....
}
and
if(reallyLongStringVariableName.In("string1","string2","string3"))
{
// do something....
}
and
if(reallyLongMethodParameterName.In(SomeEnum.Value1, SomeEnum.Value2, SomeEnum.Value3, SomeEnum.Value4)
{
// do something....
}
HTH。这些是我的一些主要问题。
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
namespace Insert.Your.Namespace.Here.Helpers
{
public static class Extensions
{
public static bool IsNullOrEmpty<T>(this IEnumerable<T> iEnumerable)
{
// Cheers to Joel Mueller for the bugfix. Was .Count(), now it's .Any()
return iEnumerable == null ||
!iEnumerable.Any();
}
public static IList<T> ToListIfNotNullOrEmpty<T>(this IList<T> iList)
{
return iList.IsNullOrEmpty() ? null : iList;
}
public static PagedList<T> ToPagedListIfNotNullOrEmpty<T>(this PagedList<T> pagedList)
{
return pagedList.IsNullOrEmpty() ? null : pagedList;
}
public static string ToPluralString(this int value)
{
return value == 1 ? string.Empty : "s";
}
public static string ToReadableTime(this DateTime value)
{
TimeSpan span = DateTime.Now.Subtract(value);
const string plural = "s";
if (span.Days > 7)
{
return value.ToShortDateString();
}
switch (span.Days)
{
case 0:
switch (span.Hours)
{
case 0:
if (span.Minutes == 0)
{
return span.Seconds <= 0
? "now"
: string.Format("{0} second{1} ago",
span.Seconds,
span.Seconds != 1 ? plural : string.Empty);
}
return string.Format("{0} minute{1} ago",
span.Minutes,
span.Minutes != 1 ? plural : string.Empty);
default:
return string.Format("{0} hour{1} ago",
span.Hours,
span.Hours != 1 ? plural : string.Empty);
}
default:
return string.Format("{0} day{1} ago",
span.Days,
span.Days != 1 ? plural : string.Empty);
}
}
public static string ToShortGuidString(this Guid value)
{
return Convert.ToBase64String(value.ToByteArray())
.Replace("/", "_")
.Replace("+", "-")
.Substring(0, 22);
}
public static Guid FromShortGuidString(this string value)
{
return new Guid(Convert.FromBase64String(value.Replace("_", "/")
.Replace("-", "+") + "=="));
}
public static string ToStringMaximumLength(this string value, int maximumLength)
{
return ToStringMaximumLength(value, maximumLength, "...");
}
public static string ToStringMaximumLength(this string value, int maximumLength, string postFixText)
{
if (string.IsNullOrEmpty(postFixText))
{
throw new ArgumentNullException("postFixText");
}
return value.Length > maximumLength
? string.Format(CultureInfo.InvariantCulture,
"{0}{1}",
value.Substring(0, maximumLength - postFixText.Length),
postFixText)
:
value;
}
public static string SlugDecode(this string value)
{
return value.Replace("_", " ");
}
public static string SlugEncode(this string value)
{
return value.Replace(" ", "_");
}
}
}
我的转换扩展，允许你做:
int i = myString.To<int>();
这是在TheSoftwareJedi.com上发布的
public static T To<T>(this IConvertible obj)
{
return (T)Convert.ChangeType(obj, typeof(T));
}
public static T ToOrDefault<T>
(this IConvertible obj)
{
try
{
return To<T>(obj);
}
catch
{
return default(T);
}
}
public static bool ToOrDefault<T>
(this IConvertible obj,
out T newObj)
{
try
{
newObj = To<T>(obj);
return true;
}
catch
{
newObj = default(T);
return false;
}
}
public static T ToOrOther<T>
(this IConvertible obj,
T other)
{
try
{
return To<T>obj);
}
catch
{
return other;
}
}
public static bool ToOrOther<T>
(this IConvertible obj,
out T newObj,
T other)
{
try
{
newObj = To<T>(obj);
return true;
}
catch
{
newObj = other;
return false;
}
}
public static T ToOrNull<T>
(this IConvertible obj)
where T : class
{
try
{
return To<T>(obj);
}
catch
{
return null;
}
}
public static bool ToOrNull<T>
(this IConvertible obj,
out T newObj)
where T : class
{
try
{
newObj = To<T>(obj);
return true;
}
catch
{
newObj = null;
return false;
}
}
您可以在失败时请求default(调用空白构造函数或“0”作为数字)，指定一个“default”值(我称之为“other”)，或请求null(其中T: class)。我还提供了两个静默异常模型和一个典型的TryParse模型，该模型返回一个bool值，指示所采取的操作，一个out参数保存新值。
我们的代码可以这样做
int i = myString.To<int>();
string a = myInt.ToOrDefault<string>();
//note type inference
DateTime d = myString.ToOrOther(DateTime.MAX_VALUE);
double d;
//note type inference
bool didItGiveDefault = myString.ToOrDefault(out d);
string s = myDateTime.ToOrNull<string>();
我不能让Nullable类型非常干净地滚入整个东西。我试了大约20分钟才认输。
public static bool In<T>(this T source, params T[] list)
{
if(null==source) throw new ArgumentNullException("source");
return list.Contains(source);
}
允许我替换:
if(reallyLongIntegerVariableName == 1 ||
reallyLongIntegerVariableName == 6 ||
reallyLongIntegerVariableName == 9 ||
reallyLongIntegerVariableName == 11)
{
// do something....
}
and
if(reallyLongStringVariableName == "string1" ||
reallyLongStringVariableName == "string2" ||
reallyLongStringVariableName == "string3")
{
// do something....
}
and
if(reallyLongMethodParameterName == SomeEnum.Value1 ||
reallyLongMethodParameterName == SomeEnum.Value2 ||
reallyLongMethodParameterName == SomeEnum.Value3 ||
reallyLongMethodParameterName == SomeEnum.Value4)
{
// do something....
}
:
if(reallyLongIntegerVariableName.In(1,6,9,11))
{
// do something....
}
and
if(reallyLongStringVariableName.In("string1","string2","string3"))
{
// do something....
}
and
if(reallyLongMethodParameterName.In(SomeEnum.Value1, SomeEnum.Value2, SomeEnum.Value3, SomeEnum.Value4)
{
// do something....
}
