C# 反模式

C# Antipatterns

提问by exhuma

To cut a long story short: I find the Java antipatternsan indispensable resource. For beginners as much as for professionals. I have yet to find something like this for C#. So I'll open up this question as community wiki and invite everyone to share their knowledge on this. As I am new to C#, I am strongly interested in this, but cannot start with some antipatterns :/

长话短说：我发现Java 反模式是不可或缺的资源。对于初学者和专业人士一样。我还没有为 C# 找到类似的东西。所以我将这个问题作为社区维基公开，并邀请每个人分享他们的知识。由于我是 C# 的新手，我对此非常感兴趣，但不能从一些反模式开始：/

Here are the answers which I find specifically true for C# and not other languages.

以下是我发现特别适用于 C# 而不是其他语言的答案。

I just copy/pasted these! Consider throwing a look on the comments on these as well.

我只是复制/粘贴这些！考虑看看对这些的评论。

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Throwing NullReferenceException

投掷 NullReferenceException

Throwing the wrong exception:

抛出错误的异常：

if (FooLicenceKeyHolder == null)
    throw new NullReferenceException();

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Properties vs. public Variables

属性与公共变量

Public variables in classes (use a property instead).

类中的公共变量（改用属性）。

Unlessthe class is a simple Data Transfer Object.

除非该类是一个简单的数据传输对象。

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Not understanding that bool is a real type, not just a convention

不明白 bool 是一个真正的类型，而不仅仅是一个约定

if (myBooleanVariable == true)
{
    ...
}

or, even better

或者，甚至更好

if (myBooleanVariable != false)
{
    ...
}

Constructs like these are often used by Cand C++developers where the idea of a boolean value was just a convention (0 == false, anything else is true); this is not necessary (or desirable) in C# or other languages that have real booleans.

这样的结构通常使用C和C++开发，其中一个布尔值的想法只是一个约定（0 ==假的，什么都为true）; 这在 C# 或其他具有真正布尔值的语言中不是必需的（或不可取的）。

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Using using()

使用 using()

Not making use of usingwhere appropriate:

没有using在适当的地方使用：

object variable;
variable.close(); //Old code, use IDisposable if available.
variable.Dispose(); //Same as close.  Avoid if possible use the using() { } pattern.
variable = null; //1. in release optimised away.  2. C# is GC so this doesn't do what was intended anyway.

回答by Robert Harvey

Public variables in classes (use a property instead).

类中的公共变量（改用属性）。

Unlessthe class is a simple Data Transfer Object.

除非该类是一个简单的数据传输对象。

See comments below for discussion and clarification.

请参阅下面的评论以进行讨论和澄清。

回答by leppie

int foo = 100;
int bar = int.Parse(foo.ToString());

Or the more general case:

或者更一般的情况：

object foo = 100;
int bar = int.Parse(foo.ToString());

回答by Andrew Keith

is this considered general ?

这被认为是通用的吗？

public static main(string [] args)
{
  quit = false;
  do
  {
  try
  {
      // application runs here .. 
      quit = true;
  }catch { }
  }while(quit == false);
}

I dont know how to explain it, but its like someone catching an exception and retrying the code over and over hoping it works later. Like if a IOException occurs, they just try over and over until it works..

我不知道如何解释它，但这就像有人捕获异常并一遍又一遍地重试代码，希望它以后能正常工作。就像发生 IOException 一样，他们只是一遍又一遍地尝试，直到它起作用为止。

回答by Ralph Lavelle

Massively over-complicated 'Page_Load' methods, which want to do everything.

大量过于复杂的“Page_Load”方法，它们想要做任何事情。

回答by Spence

object variable;
variable.close(); //Old code, use IDisposable if available.
variable.Dispose(); //Same as close.  Avoid if possible use the using() { } pattern.
variable = null; //1. in release optimised away.  2. C# is GC so this doesn't do what was intended anyway.

回答by Andrew Keith

GC.Collect()to collect instead of trusting the garbage collector.

GC.Collect()收集而不是信任垃圾收集器。

回答by leppie

Insulting the law of Demeter:

侮辱德墨忒尔定律：

a.PropertyA.PropertyC.PropertyB.PropertyE.PropertyA = 
     b.PropertyC.PropertyE.PropertyA;

回答by rein

Rethrowing the exception incorrectly. To rethrow an exception :

错误地重新抛出异常。重新抛出异常：

try
{
    // do some stuff here
}
catch (Exception ex)
{
    throw ex;  // INCORRECT
    throw;     // CORRECT
    throw new Exception("There was an error"); // INCORRECT
    throw new Exception("There was an error", ex); // CORRECT
}

回答by leppie

Private auto-implemented properties:

私有自动实现的属性：

private Boolean MenuExtended { get; set; }

回答by anthony

• Lack of null test before delegate invocation.
• Not knowing when and how to use 'as' with a null check vs. a cast with a try/catch.
• 'throw exception' vs. 'throw' within a catch block.
• Instantiating a large number of strings instead of using StringBuilder.
• Deep nesting of using blocks.

• 委托调用前缺少空测试。
• 不知道何时以及如何使用带有空检查的“as”与带有 try/catch 的强制转换。
• 在 catch 块中“抛出异常”与“抛出”。
• 实例化大量字符串而不是使用 StringBuilder。
• 使用块的深层嵌套。