到目前为止，我刚刚浏览了所有4页，我很惊讶，我没有看到这种方式来缩短检查InvokeRequired:

using System;
using System.Windows.Forms;

/// <summary>
/// Extension methods acting on Control objects.
/// </summary>
internal static class ControlExtensionMethods
{
    /// <summary>
    /// Invokes the given action on the given control's UI thread, if invocation is needed.
    /// </summary>
    /// <param name="control">Control on whose UI thread to possibly invoke.</param>
    /// <param name="action">Action to be invoked on the given control.</param>
    public static void MaybeInvoke(this Control control, Action action)
    {
        if (control != null && control.InvokeRequired)
        {
            control.Invoke(action);
        }
        else
        {
            action();
        }
    }

    /// <summary>
    /// Maybe Invoke a Func that returns a value.
    /// </summary>
    /// <typeparam name="T">Return type of func.</typeparam>
    /// <param name="control">Control on which to maybe invoke.</param>
    /// <param name="func">Function returning a value, to invoke.</param>
    /// <returns>The result of the call to func.</returns>
    public static T MaybeInvoke<T>(this Control control, Func<T> func)
    {
        if (control != null && control.InvokeRequired)
        {
            return (T)(control.Invoke(func));
        }
        else
        {
            return func();
        }
    }
}

用法:

myForm.MaybeInvoke(() => this.Text = "Hello world");

// Sometimes the control might be null, but that's okay.
var dialogResult = this.Parent.MaybeInvoke(() => MessageBox.Show(this, "Yes or no?", "Choice", MessageBoxButtons.YesNo));

我们有一个部署工具可以在不同环境之间进行部署。由于文件可以标记为修改，但实际上没有不同，我想出了这个:

/// <summary>
/// Compares the files to see if they are different. 
/// First checks file size
/// Then modified if the file is larger than the specified size
/// Then compares the bytes
/// </summary>
/// <param name="file1">The source file</param>
/// <param name="file2">The destination file</param>
/// <param name="mb">Skip the smart check if the file is larger than this many megabytes. Default is 10.</param>
/// <returns></returns>
public static bool IsDifferentThan(this FileInfo file1, FileInfo file2, int mb = 10)
{
  var ret = false;

  // different size is a different file
  if(file1.Length != file2.Length) return true;

  // if the file times are different and the file is bigger than 10mb flag it for updating
  if(file1.LastWriteTimeUtc > file2.LastWriteTimeUtc && file1.Length > ((mb*1024)*1024)) return true;

  var f1 = File.ReadAllBytes(file1.FullName);
  var f2 = File.ReadAllBytes(file2.FullName);

  // loop through backwards because if they are different
  // it is more likely that the last few bytes will be different
  // than the first few
  for(var i = file1.Length - 1; i > 0; i--)
  {
    if(f1[i] != f2[i])
    {
      ret = true;
      break;
    }
  }

  return ret;
}

将double类型转换为使用指定区域性格式化的字符串:

public static class ExtensionMethods 
{
  public static string ToCurrency(this double value, string cultureName)
  {
    CultureInfo currentCulture = new CultureInfo(cultureName);
    return (string.Format(currentCulture, "{0:C}", value));
  }
}

例子:

double test = 154.20;
string testString = test.ToCurrency("en-US"); // $154.20

这些有用吗?

public static bool CoinToss(this Random rng)
{
    return rng.Next(2) == 0;
}

public static T OneOf<T>(this Random rng, params T[] things)
{
    return things[rng.Next(things.Length)];
}

Random rand;
bool luckyDay = rand.CoinToss();
string babyName = rand.OneOf("John", "George", "Radio XBR74 ROCKS!");

gitorious.org/cadenza是我所见过的一些最有用的扩展方法的完整库。

这一个是MVC，它添加了生成一个<label />标签到Html变量的能力，在每个ViewPage中可用。希望它能对其他试图开发类似扩展的人有所帮助。

Use:

<%= Html.Label("LabelId", "ForId", "Text")%>

输出:

<label id="LabelId" for="ForId">Text</label>

代码:

public static class HtmlHelperExtensions
{
    public static string Label(this HtmlHelper Html, string @for, string text)
    {
        return Html.Label(null, @for, text);
    }

    public static string Label(this HtmlHelper Html, string @for, string text, object htmlAttributes)
    {
        return Html.Label(null, @for, text, htmlAttributes);
    }

    public static string Label(this HtmlHelper Html, string @for, string text, IDictionary<string, object> htmlAttributes)
    {
        return Html.Label(null, @for, text, htmlAttributes);
    }

    public static string Label(this HtmlHelper Html, string id, string @for, string text)
    {
        return Html.Label(id, @for, text, null);
    }

    public static string Label(this HtmlHelper Html, string id, string @for, string text, object htmlAttributes)
    {
        return Html.Label(id, @for, text, new RouteValueDictionary(htmlAttributes));
    }

    public static string Label(this HtmlHelper Html, string id, string @for, string text, IDictionary<string, object> htmlAttributes)
    {
        TagBuilder tag = new TagBuilder("label");

        tag.MergeAttributes(htmlAttributes);

        if (!string.IsNullOrEmpty(id))
            tag.MergeAttribute("id", Html.AttributeEncode(id));

        tag.MergeAttribute("for", Html.AttributeEncode(@for));

        tag.SetInnerText(Html.Encode(text));

        return tag.ToString(TagRenderMode.Normal);
    }
}