如何错的是它与超出标准（的OBJ发件人，EventArgs参数）签名创建一个事件处理程序委托？ [英] How wrong is it to create an event handler delegate with out the standard (Obj sender, EventArgs args) signature?

问题描述

我了解使用标准的MS事件处理程序委托签名，因为它可以让你轻松的通过事件与出打破了基于旧的委托签名的旧关系，传递的信息扩大所带来的好处。

I understand the benefits of using the standard MS event handler delegate signature as it allows you to easily expand on the information passed through the event with out breaking any old relationships that are based on the old delegate signature.

我想知道是如何在实践中往往人们遵循这一规则？说我有这样的

What I'm wondering is in practice how often do people follow this rule? Say I have a simple event like this

public event NameChangedHandler NameChanged;
public delegate void NameChangedHandler(Object sender, string oldName, string newName);

这是一个简单的事件，我几乎肯定的，唯一的争论，我曾经去需要知道从NameChanged事件是他的名字更改了对象，旧名称，新名称。因此，它是值得的，创建一个单独的NameChangedEventArgs类，或者简单的这样的活动是可以接受的，只是通过委托参数直接返回的参数？

It's a simple event, and I'm nearly positive that the only arguments I'm ever going to need to know from the NameChanged event is the object whose name changed, the old name, and the new name. So is it worth it to create a separate NameChangedEventArgs class, or for simple events like this is it acceptable to just return the the arguments directly through the delegate arguments?

推荐答案

如果你是谁拥有对付它的唯一一个你可以做任何事情，走错了路。但它不是一个坏主意，学习标准，并坚持给他们，让你继续当你的工作代码与他人的良好习惯。

You can do anything the wrong way if you're the only one who has to deal with it. But it's not a bad idea to learn standards and stick to them so that you keep good habits when you're working on code with others.

所以，我会让你一个交易。如果你答应做正确的方式，我给你的代码片段将使它更痛苦少。只是把这个在一个是.snippet文件，并将该文件中：

So I'll make you a deal. If you promise to do it the right way, I'll give you a code snippet that'll make it much less of a pain. Just put this in a .snippet file, and put that file in:

我Documents\Visual工作室2008\Code Snippets\Visual C＃\My代码段\

（或Visual Studio 2005如适用）

My Documents\Visual Studio 2008\Code Snippets\Visual C#\My Code Snippets\
(or Visual Studio 2005 if applicable)

和这里的片段; ？XML版本=1.0编码=UTF-8;

And here's the snippet; use it in VS by typing ev2Generic and hitting Tab:

<?xml version="1.0" encoding="utf-8" ?>
<CodeSnippets  xmlns="http://schemas.microsoft.com/VisualStudio/2005/CodeSnippet">
  <CodeSnippet Format="1.0.0">
    <Header>
      <Title>Generic event with two types/arguments.</Title>
      <Shortcut>ev2Generic</Shortcut>
      <Description>Code snippet for event handler and On method</Description>
      <Author>Kyralessa</Author>
      <SnippetTypes>
        <SnippetType>Expansion</SnippetType>
      </SnippetTypes>
    </Header>
    <Snippet>
      <Declarations>
        <Literal>
          <ID>type1</ID>
          <ToolTip>Type of the first property in the EventArgs subclass.</ToolTip>
          <Default>propertyType1</Default>
        </Literal>
        <Literal>
          <ID>arg1Name</ID>
          <ToolTip>Name of the first argument in the EventArgs subclass constructor.</ToolTip>
          <Default>property1Name</Default>
        </Literal>
        <Literal>
          <ID>property1Name</ID>
          <ToolTip>Name of the first property in the EventArgs subclass.</ToolTip>
          <Default>Property1Name</Default>
        </Literal>
        <Literal>
          <ID>type2</ID>
          <ToolTip>Type of the second property in the EventArgs subclass.</ToolTip>
          <Default>propertyType2</Default>
        </Literal>
        <Literal>
          <ID>arg2Name</ID>
          <ToolTip>Name of the second argument in the EventArgs subclass constructor.</ToolTip>
          <Default>property2Name</Default>
        </Literal>
        <Literal>
          <ID>property2Name</ID>
          <ToolTip>Name of the second property in the EventArgs subclass.</ToolTip>
          <Default>Property2Name</Default>
        </Literal>
        <Literal>
          <ID>eventName</ID>
          <ToolTip>Name of the event</ToolTip>
          <Default>NameOfEvent</Default>
        </Literal>
      </Declarations>
      <Code Language="CSharp">
        <![CDATA[public class $eventName$EventArgs : System.EventArgs
      {
        public $eventName$EventArgs($type1$ $arg1Name$, $type2$ $arg2Name$)
        {
          this.$property1Name$ = $arg1Name$;
          this.$property2Name$ = $arg2Name$;
        }

        public $type1$ $property1Name$ { get; private set; }
        public $type2$ $property2Name$ { get; private set; }
      }

      public event EventHandler<$eventName$EventArgs> $eventName$;
            protected virtual void On$eventName$($eventName$EventArgs e)
            {
                var handler = $eventName$;
                if (handler != null)
                    handler(this, e);
            }]]>
      </Code>
    </Snippet>
  </CodeSnippet>
</CodeSnippets>

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