TextInfo textInfo = Thread.CurrentThread.CurrentCulture.TextInfo;

textInfo.ToTitleCase("hello world!"); //Returns "Hello World!"
textInfo.ToTitleCase("hElLo WoRld!"); //Returns "Hello World!"
textInfo.ToTitleCase("Hello World!"); //Returns "Hello World!"
textInfo.ToTitleCase("HELLO WORLD!"); //Returns "HELLO WORLD!"

是的，这种行为是有记录的，但这并不能证明它是正确的。

在调试环境中求值时，base关键字不能按预期工作:方法调用仍然使用虚拟分派。

当我偶然发现它时，我浪费了很多时间，我以为我遇到了CLR时空中的某种裂缝，但我后来意识到这是一个已知的(甚至有点故意的)bug:

http://blogs.msdn.com/jmstall/archive/2006/06/29/funceval-does-virtual-dispatch.aspx

如果你正在为MOSS编写代码，你以这种方式获得一个站点引用:

SPSite oSiteCollection = SPContext.Current.Site;

之后在你的代码中你说:

oSiteCollection.Dispose();

从MSDN:

If you create an SPSite object, you can use the Dispose method to close the object. However, if you have a reference to a shared resource, such as when the object is provided by the GetContextSite method or Site property (for example, SPContext.Current.Site), do not use the Dispose method to close the object, but instead allow Windows SharePoint Services or your portal application to manage the object. For more information about object disposal, see Best Practices: Using Disposable Windows SharePoint Services Objects.

每个MOSS程序员都会遇到这种情况。

也许不是真的抓住你，因为行为写得很清楚在MSDN中，但已经打破了我的脖子，因为我发现它相当反直觉:

Image image = System.Drawing.Image.FromFile("nice.pic");

这家伙留下了“不错”。图片“文件锁定，直到图像被处置。在我面对它的时候，我认为它会很好地加载图标，并没有意识到(一开始)，我最终有几十个打开和锁定的文件!Image一直跟踪它从哪里加载文件…

如何解决这个问题?我以为只用一行就行了。我期望FromFile()有一个额外的参数，但没有，所以我写了这个…

using (Stream fs = new FileStream("nice.pic", FileMode.Open, FileAccess.Read))
{
    image = System.Drawing.Image.FromStream(fs);
}

看看这个:

class Program
{
    static void Main(string[] args)
    {
        var originalNumbers = new List<int> { 1, 2, 3, 4, 5, 6 };

        var list = new List<int>(originalNumbers);
        var collection = new Collection<int>(originalNumbers);

        originalNumbers.RemoveAt(0);

        DisplayItems(list, "List items: ");
        DisplayItems(collection, "Collection items: ");

        Console.ReadLine();
    }

    private static void DisplayItems(IEnumerable<int> items, string title)
    {
        Console.WriteLine(title);
        foreach (var item in items)
            Console.Write(item);
        Console.WriteLine();
    }
}

输出是:

List items: 123456
Collection items: 23456

接受IList的集合构造函数会对原始List创建一个包装器，而List构造函数会创建一个新List并将所有引用从原始List复制到新List。

点击这里查看更多信息: http://blog.roboblob.com/2012/09/19/dot-net-gotcha-nr1-list-versus-collection-constructor/

不是最糟糕的，但还没被提起。工厂方法作为参数传递给System.Collections.Concurrent方法可以被多次调用，即使只使用了一个返回值。考虑到. net在线程原语中多么强烈地试图保护您不受虚假唤醒的影响，这可能会让您感到惊讶。

using System;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace ValueFactoryBehavingBadlyExample
{
    class Program
    {
        static ConcurrentDictionary<int, int> m_Dict = new ConcurrentDictionary<int, int>();
        static ManualResetEventSlim m_MRES = new ManualResetEventSlim(false);
        static void Main(string[] args)
        {
            for (int i = 0; i < 8; ++i)
            {
                Task.Factory.StartNew(ThreadGate, TaskCreationOptions.LongRunning);
            }
            Thread.Sleep(1000);
            m_MRES.Set();
            Thread.Sleep(1000);
            Console.WriteLine("Dictionary Size: " + m_Dict.Count);
            Console.Read();
        }

        static void ThreadGate()
        {
            m_MRES.Wait();
            int value = m_Dict.GetOrAdd(0, ValueFactory);
        }

        static int ValueFactory(int key)
        {
            Thread.Sleep(1000);
            Console.WriteLine("Value Factory Called");
            return key;
        }
    }
}

(可能)输出:

Value Factory Called
Value Factory Called
Value Factory Called
Value Factory Called
Dictionary Size: 0
Value Factory Called
Value Factory Called
Value Factory Called
Value Factory Called