避免参数的解析模式:

public static bool TryParseInt32(this string input, Action<int> action)
{
    int result;
    if (Int32.TryParse(input, out result))
    {
        action(result);
        return true;
    }
    return false;
}

用法:

if (!textBox.Text.TryParseInt32(number => label.Text = SomeMathFunction(number)))
    label.Text = "Please enter a valid integer";

这可以放在codeplex项目中，如果需要的话

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;
        }
    }
}

// This file contains extension methods for generic List<> class to operate on sorted lists.
// Duplicate values are OK.
// O(ln(n)) is still much faster then the O(n) of LINQ's searches/filters.
static partial class SortedList
{
    // Return the index of the first element with the key greater then provided.
    // If there's no such element within the provided range, it returns iAfterLast.
    public static int sortedFirstGreaterIndex<tElt, tKey>( this IList<tElt> list, Func<tElt, tKey, int> comparer, tKey key, int iFirst, int iAfterLast )
    {
        if( iFirst < 0 || iAfterLast < 0 || iFirst > list.Count || iAfterLast > list.Count )
            throw new IndexOutOfRangeException();
        if( iFirst > iAfterLast )
            throw new ArgumentException();
        if( iFirst == iAfterLast )
            return iAfterLast;

        int low = iFirst, high = iAfterLast;
        // The code below is inspired by the following article:
        // http://en.wikipedia.org/wiki/Binary_search#Single_comparison_per_iteration
        while( low < high )
        {
            int mid = ( high + low ) / 2;
            // 'mid' might be 'iFirst' in case 'iFirst+1 == iAfterLast'.
            // 'mid' will never be 'iAfterLast'.
            if( comparer( list[ mid ], key ) <= 0 ) // "<=" since we gonna find the first "greater" element
                low = mid + 1;
            else
                high = mid;
        }
        return low;
    }

    // Return the index of the first element with the key greater then the provided key.
    // If there's no such element, returns list.Count.
    public static int sortedFirstGreaterIndex<tElt, tKey>( this IList<tElt> list, Func<tElt, tKey, int> comparer, tKey key )
    {
        return list.sortedFirstGreaterIndex( comparer, key, 0, list.Count );
    }

    // Add an element to the sorted array.
    // This could be an expensive operation if frequently adding elements that sort firstly.
    // This is cheap operation when adding elements that sort near the tail of the list.
    public static int sortedAdd<tElt>( this List<tElt> list, Func<tElt, tElt, int> comparer, tElt elt )
    {
        if( list.Count == 0 || comparer( list[ list.Count - 1 ], elt ) <= 0 )
        {
            // either the list is empty, or the item is greater then all elements already in the collection.
            list.Add( elt );
            return list.Count - 1;
        }
        int ind = list.sortedFirstGreaterIndex( comparer, elt );
        list.Insert( ind, elt );
        return ind;
    }

    // Find first exactly equal element, return -1 if not found.
    public static int sortedFindFirstIndex<tElt, tKey>( this List<tElt> list, Func<tElt, tKey, int> comparer, tKey elt )
    {
        int low = 0, high = list.Count - 1;

        while( low < high )
        {
            int mid = ( high + low ) / 2;
            if( comparer( list[ mid ], elt ) < 0 )
                low = mid + 1;
            else
                high = mid; // this includes the case when we've found an element exactly matching the key
        }
        if( high >= 0 && 0 == comparer( list[ high ], elt ) )
            return high;
        return -1;
    }

    // Return the IEnumerable that returns array elements in the reverse order.
    public static IEnumerable<tElt> sortedReverse<tElt>( this List<tElt> list )
    {
        for( int i=list.Count - 1; i >= 0; i-- )
            yield return list[ i ];
    }
}

而与MVC工作，有很多if语句，我只关心或真或假，打印null，或字符串。在另一种情况下，我想到了:

public static TResult WhenTrue<TResult>(this Boolean value, Func<TResult> expression)
{
    return value ? expression() : default(TResult);
}

public static TResult WhenTrue<TResult>(this Boolean value, TResult content)
{
    return value ? content : default(TResult);
}

public static TResult WhenFalse<TResult>(this Boolean value, Func<TResult> expression)
{
    return !value ? expression() : default(TResult);
}

public static TResult WhenFalse<TResult>(this Boolean value, TResult content)
{
    return !value ? content : default(TResult);
}

它允许我改变<%= (someBool) ?print y:字符串。将%>空为<%= someBool。WhenTrue("print y") %>。

我只在我的视图中使用它，在这里我混合了代码和HTML，在代码文件中编写“更长的”版本更清楚。

NullPartial用于ASP MVC的HTML helper。

当传递一个空模型时，HTML。Partial和HTML。RenderPartial将提供视图的模型，如果这个部分是强类型的，而视图有不同的类型，它将抛出一个异常，而不是传递一个空引用。这些帮助程序允许您指定两个不同的部分，这样您就可以将空测试排除在视图之外。

您有权在Codeplex页面上包含此内容

public static class nullpartials
    {
        public static MvcHtmlString NullPartial(this HtmlHelper helper, string Partial, string NullPartial, object Model)
        {
            if (Model == null)
                return helper.Partial(NullPartial);
            else
                return helper.Partial(Partial, Model);
        }

        public static MvcHtmlString NullPartial(this HtmlHelper helper, string Partial, string NullPartial, object Model, ViewDataDictionary viewdata)
        {
            if (Model == null)
                return helper.Partial(NullPartial, viewdata);
            else
                return helper.Partial(Partial, Model, viewdata);
        }

        public static void RenderNullPartial(this HtmlHelper helper, string Partial, string NullPartial, object Model)
        {
            if (Model == null)
            {
                helper.RenderPartial(NullPartial);
                return;
            }
            else
            {
                helper.RenderPartial(Partial, Model);
                return;
            }
        }

        public static void RenderNullPartial(this HtmlHelper helper, string Partial, string NullPartial, object Model, ViewDataDictionary viewdata)
        {
            if (Model == null)
            {
                helper.RenderPartial(NullPartial, viewdata);
                return;
            }
            else
            {
                helper.RenderPartial(Partial, Model, viewdata);
                return;
            }
        }
    }

获取URI的根域。

/// <summary>Gets the root domain of any URI</summary>
/// <param name="uri">URI to get root domain of</param>
/// <returns>Root domain with TLD</returns>
public static string GetRootDomain(this System.Uri uri)
{
    if (uri == null)
        return null;

    string Domain = uri.Host;
    while (System.Text.RegularExpressions.Regex.Matches(Domain, @"[\.]").Count > 1)
        Domain = Domain.Substring(Domain.IndexOf('.') + 1);
    Domain = Domain.Substring(0, Domain.IndexOf('.'));
    return Domain;
}