这一次是为了使UriBuilder在处理查询参数时更加友好。

    /// <summary>
    /// Adds the specified query parameter to the URI builder.
    /// </summary>
    /// <param name="builder">The builder.</param>
    /// <param name="parameterName">Name of the parameter.</param>
    /// <param name="value">The URI escaped value.</param>
    /// <returns>The final full query string.</returns>
    public static string AddQueryParam(this UriBuilder builder, string parameterName, string value)
    {
        if (parameterName == null)
            throw new ArgumentNullException("parameterName");

        if (parameterName.Length == 0)
            throw new ArgumentException("The parameter name is empty.");

        if (value == null)
            throw new ArgumentNullException("value");

        if (value.Length == 0)
            throw new ArgumentException("The value is empty.");

        if (builder.Query.Length == 0)
        {
            builder.Query = String.Concat(parameterName, "=", value);
        }
        else if
            (builder.Query.Contains(String.Concat("&", parameterName, "="))
            || builder.Query.Contains(String.Concat("?", parameterName, "=")))
        {
            throw new InvalidOperationException(String.Format("The parameter {0} already exists.", parameterName));
        }
        else
        {
            builder.Query = String.Concat(builder.Query.Substring(1), "&", parameterName, "=", value);
        }

        return builder.Query;
    }

当使用键为字符串的字典时，使用不区分大小写的搜索返回现有的键。我们的用例是文件路径。

/// <summary>
/// Gets the key using <paramref name="caseInsensitiveKey"/> from <paramref name="dictionary"/>.
/// </summary>
/// <typeparam name="T">The dictionary value.</typeparam>
/// <param name="dictionary">The dictionary.</param>
/// <param name="caseInsensitiveKey">The case insensitive key.</param>
/// <returns>
/// An existing key; or <see cref="string.Empty"/> if not found.
/// </returns>
public static string GetKeyIgnoringCase<T>(this IDictionary<string, T> dictionary, string caseInsensitiveKey)
{
    if (string.IsNullOrEmpty(caseInsensitiveKey)) return string.Empty;
    foreach (string key in dictionary.Keys)
    {
        if (key.Equals(caseInsensitiveKey, StringComparison.InvariantCultureIgnoreCase))
        {
            return key;
        }
    }
    return string.Empty;
}

For adding multiple elements to a collection that doesn't have AddRange, e.g., collection.Add(item1, item2, itemN); static void Add<T>(this ICollection<T> coll, params T[] items) { foreach (var item in items) coll.Add(item); } The following is like string.Format() but with custom string representation of arguments, e.g., "{0} {1} {2}".Format<Custom>(c=>c.Name,"string",new object(),new Custom()) results in "string {System.Object} Custom1Name" static string Format<T>( this string format , Func<T,object> select , params object[] args) { for(int i=0; i < args.Length; ++i) { var x = args[i] as T; if (x != null) args[i] = select(x); } return string.Format(format, args); }

通过操作系统文件系统信息比较文件/目录。这对于比较共享和本地文件非常有用。

用法:

DirectoryInfo dir = new DirectoryInfo(@"C:\test\myShareDir");
Console.WriteLine(dir.IsSameFileAs(@"\\myMachineName\myShareDir"));

FileInfo file = new FileInfo(@"C:\test\myShareDir\file.txt");
Console.WriteLine(file.IsSameFileAs(@"\\myMachineName\myShareDir\file.txt"));

代码:

public static class FileExtensions
{
    struct BY_HANDLE_FILE_INFORMATION
    {
        public uint FileAttributes;
        public System.Runtime.InteropServices.ComTypes.FILETIME CreationTime;
        public System.Runtime.InteropServices.ComTypes.FILETIME LastAccessTime;
        public System.Runtime.InteropServices.ComTypes.FILETIME LastWriteTime;
        public uint VolumeSerialNumber;
        public uint FileSizeHigh;
        public uint FileSizeLow;
        public uint NumberOfLinks;
        public uint FileIndexHigh;
        public uint FileIndexLow;
    }

    //
    // CreateFile constants
    //
    const uint FILE_SHARE_READ = 0x00000001;
    const uint OPEN_EXISTING = 3;
    const uint GENERIC_READ = (0x80000000);
    const uint FILE_FLAG_BACKUP_SEMANTICS = 0x02000000;


    [DllImport("kernel32.dll", SetLastError = true)]
    static extern IntPtr CreateFile(
        string lpFileName,
        uint dwDesiredAccess,
        uint dwShareMode,
        IntPtr lpSecurityAttributes,
        uint dwCreationDisposition,
        uint dwFlagsAndAttributes,
        IntPtr hTemplateFile);

    [DllImport("kernel32.dll", SetLastError = true)]
    static extern bool GetFileInformationByHandle(IntPtr hFile, out BY_HANDLE_FILE_INFORMATION lpFileInformation);

    public static bool IsSameFileAs(this FileSystemInfo file, string path)
    {
        BY_HANDLE_FILE_INFORMATION fileInfo1, fileInfo2;
        IntPtr ptr1 = CreateFile(file.FullName, GENERIC_READ, FILE_SHARE_READ, IntPtr.Zero, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, IntPtr.Zero);
        if ((int)ptr1 == -1)
        {
            System.ComponentModel.Win32Exception e = new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
            throw e;
        }
        IntPtr ptr2 = CreateFile(path, GENERIC_READ, FILE_SHARE_READ, IntPtr.Zero, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, IntPtr.Zero);
        if ((int)ptr2 == -1)
        {
            System.ComponentModel.Win32Exception e = new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
            throw e;
        }
        GetFileInformationByHandle(ptr1, out fileInfo1);
        GetFileInformationByHandle(ptr2, out fileInfo2);

        return ((fileInfo1.FileIndexHigh == fileInfo2.FileIndexHigh) &&
            (fileInfo1.FileIndexLow == fileInfo2.FileIndexLow));
    }
}

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(" ", "_");
        }
    }
}

我有一个扩展方法记录异常:

public static void Log(this Exception obj)
{
  //your logging logic here
}

它的用法是这样的:

try
{
    //Your stuff here
}
catch(Exception ex)
{
    ex.Log();
}

[抱歉发了两次;第二个设计得更好:-)]