使用标准（Obj sender，EventArgs args）签名创建事件处理程序委托有多错误？ [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MS事件处理程序委托签名的好处，因为它允许您轻松扩展通过事件传递的信息，而不会破坏基于旧代理签名的旧关系。

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.

我想知道的是，人们遵循这个规则多久？说我有这样一个简单的事件

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，我几乎是积极的，我唯一的争论需要知道的NameChanged事件是其名称更改的对象，旧名称和新名称。那么创建一个单独的NameChangedEventArgs类是值得的，还是直接通过委托参数直接返回参数的简单事件呢？

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

如果你是唯一需要处理的人，你可以做错事。但是，学习标准并坚持下去并不是个好主意，以便在与他人合作编写代码时保持良好的习惯。

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。如果你承诺以正确的方式做到这一点，我会给你一个代码片段，这样做会减轻痛苦。只需将其放在.snippet文件中，并将该文件放入：

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:

我的文档\Visual Studio 2008\Code Snippets \Visual C＃\My代码段\

（或Visual Studio 2005（如果适用））

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

这里是代码段;在VS中使用它，键入ev2Generic并点击Tab：

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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