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。
我使用以下扩展来扩展所有的集合(也许有人发现这些有用):
/// <summary>
/// Collection Helper
/// </summary>
/// <remarks>
/// Use IEnumerable by default, but when altering or getting item at index use IList.
/// </remarks>
public static class CollectionHelper
{
#region Alter;
/// <summary>
/// Swap item to another place
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <param name="IndexA">Index a</param>
/// <param name="IndexB">Index b</param>
/// <returns>New collection</returns>
public static IList<T> Swap<T>(this IList<T> @this, Int32 IndexA, Int32 IndexB)
{
T Temp = @this[IndexA];
@this[IndexA] = @this[IndexB];
@this[IndexB] = Temp;
return @this;
}
/// <summary>
/// Swap item to the left
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <param name="Index">Index</param>
/// <returns>New collection</returns>
public static IList<T> SwapLeft<T>(this IList<T> @this, Int32 Index)
{
return @this.Swap(Index, Index - 1);
}
/// <summary>
/// Swap item to the right
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <param name="Index">Index</param>
/// <returns>New collection</returns>
public static IList<T> SwapRight<T>(this IList<T> @this, Int32 Index)
{
return @this.Swap(Index, Index + 1);
}
#endregion Alter;
#region Action;
/// <summary>
/// Execute action at specified index
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <param name="Index">Index</param>
/// <param name="ActionAt">Action to execute</param>
/// <returns>New collection</returns>
public static IList<T> ActionAt<T>(this IList<T> @this, Int32 Index, Action<T> ActionAt)
{
ActionAt(@this[Index]);
return @this;
}
#endregion Action;
#region Randomize;
/// <summary>
/// Take random items
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <param name="Count">Number of items to take</param>
/// <returns>New collection</returns>
public static IEnumerable<T> TakeRandom<T>(this IEnumerable<T> @this, Int32 Count)
{
return @this.Shuffle().Take(Count);
}
/// <summary>
/// Take random item
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <returns>Item</returns>
public static T TakeRandom<T>(this IEnumerable<T> @this)
{
return @this.TakeRandom(1).Single();
}
/// <summary>
/// Shuffle list
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <returns>New collection</returns>
public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> @this)
{
return @this.OrderBy(Item => Guid.NewGuid());
}
#endregion Randomize;
#region Navigate;
/// <summary>
/// Get next item in collection and give first item, when last item is selected;
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <param name="Index">Index in collection</param>
/// <returns>Next item</returns>
public static T Next<T>(this IList<T> @this, ref Int32 Index)
{
Index = ++Index >= 0 && Index < @this.Count ? Index : 0;
return @this[Index];
}
/// <summary>
/// Get previous item in collection and give last item, when first item is selected;
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <param name="Index">Index in collection</param>
/// <returns>Previous item</returns>
public static T Previous<T>(this IList<T> @this, ref Int32 Index)
{
Index = --Index >= 0 && Index < @this.Count ? Index : @this.Count - 1;
return @this[Index];
}
#endregion Navigate;
#region Clone;
/// <summary>
///
/// </summary>
/// <typeparam name="T">Collection type</typeparam>
/// <param name="this">Collection</param>
/// <returns>Cloned collection</returns>
public static IEnumerable<T> Clone<T>(this IEnumerable<T> @this) where T : ICloneable
{
return @this.Select(Item => (T)Item.Clone());
}
#endregion Clone;
#region String;
/// <summary>
/// Joins multiple string with Separator
/// </summary>
/// <param name="this">Collection</param>
/// <param name="Separator">Separator</param>
/// <returns>Joined string</returns>
public static String Join(this IEnumerable<String> @this, String Separator = "")
{
return String.Join(Separator, @this);
}
#endregion String;
}
这是ThrowIfNull的另一个实现:
[ThreadStatic]
private static string lastMethodName = null;
[ThreadStatic]
private static int lastParamIndex = 0;
[MethodImpl(MethodImplOptions.NoInlining)]
public static void ThrowIfNull<T>(this T parameter)
{
var currentStackFrame = new StackFrame(1);
var props = currentStackFrame.GetMethod().GetParameters();
if (!String.IsNullOrEmpty(lastMethodName)) {
if (currentStackFrame.GetMethod().Name != lastMethodName) {
lastParamIndex = 0;
} else if (lastParamIndex >= props.Length - 1) {
lastParamIndex = 0;
} else {
lastParamIndex++;
}
} else {
lastParamIndex = 0;
}
if (!typeof(T).IsValueType) {
for (int i = lastParamIndex; i < props.Length; i++) {
if (props[i].ParameterType.IsValueType) {
lastParamIndex++;
} else {
break;
}
}
}
if (parameter == null) {
string paramName = props[lastParamIndex].Name;
throw new ArgumentNullException(paramName);
}
lastMethodName = currentStackFrame.GetMethod().Name;
}
它不像其他实现那样高效,但有更干净的用法:
public void Foo()
{
Bar(1, 2, "Hello", "World"); //no exception
Bar(1, 2, "Hello", null); //exception
Bar(1, 2, null, "World"); //exception
}
public void Bar(int x, int y, string someString1, string someString2)
{
//will also work with comments removed
//x.ThrowIfNull();
//y.ThrowIfNull();
someString1.ThrowIfNull();
someString2.ThrowIfNull();
//Do something incredibly useful here!
}
改变参数为int?也会起作用。
那
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。
字符串。格式的快捷方式:
public static class StringExtensions
{
// Enable quick and more natural string.Format calls
public static string F(this string s, params object[] args)
{
return string.Format(s, args);
}
}
例子:
var s = "The co-ordinate is ({0}, {1})".F(point.X, point.Y);
要快速复制粘贴,请点击这里。
难道你不觉得输入“一些字符串”. f(“param”)而不是字符串更自然吗?格式(“一些字符串”,“参数”)?
想要一个更容易读懂的名字,试试下面的建议:
s = "Hello {0} world {1}!".Fmt("Stack", "Overflow");
s = "Hello {0} world {1}!".FormatBy("Stack", "Overflow");
s = "Hello {0} world {1}!".FormatWith("Stack", "Overflow");
s = "Hello {0} world {1}!".Display("Stack", "Overflow");
s = "Hello {0} world {1}!".With("Stack", "Overflow");
..