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For a program I'm making I'm using object to hold the value of HTML attributes. There's a bunch if things I do with these values in the whole program. So I would basically like to create an alias for object whenever is used to hold values of HTML attributes to something like AttrValue just to make the program more clear, and to be able to easily add functionality if needed. These objects are used on critical-performance parts of the program, so I'm not sure if making a class instead of a struct would be the best idea. What would it be the best solution here, if performance is the main concern (more than clearness actually)?

Juan
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  • Do you know about interfaces and/or inheritance? – strager Aug 12 '10 at 16:49
  • I don't understand what you are saying. "create an alias for object" -- what is that supposed to mean? – Kirk Woll Aug 12 '10 at 16:50
  • @Kirk Woll, It seems like @jsoldi wants type safety in their system. – strager Aug 12 '10 at 16:51
  • Also, by default, all classes inherit from `object` (`System.Object`). – strager Aug 12 '10 at 16:53
  • well, on C++ you could do stuff like: `typedef SomeClass AttrValue;` That means `AttrValue` is just a `SomeClass` but with another name. In C# would be basically the same as `class AttrValue : SomeClass {}` but I don't know what's the best way to use `object` instead of `SomeClass`. – Juan Aug 12 '10 at 16:54
  • In C# you can do `using AttrValue = object;` but it's purely a cosmetic change for your own source code - other people consuming your library would just see `object`. – Joel Mueller Aug 12 '10 at 16:56

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You can create a type alias like using AttrValue = System.Object;. However, this alias will only exist in your source code. There's nothing stopping you from using, say, object or string where you need an AttrValue. You won't be able to add properties or methods onto your AttrValue alias: it will be an alias for object and not a class in its own right.

You're probably better off introducing AttrValue as a class in its own right, presumably as a wrapper for a value of type object. It might have a single field (of type object), and a constructor that takes one object parameter.

Regarding struct vs. class, I wouldn't worry about this. You almost never need a struct in .NET code: the garbage collector is capable of handling lots of small class instances without noticeable overhead, and structs have their own oddities (mainly because what looks like the same instance in source code can easily end up being two separate copies at run time).

Community
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Tim Robinson
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  • I believe if I use `using AttrValue = System.Object` I would need to put that on every file I need object to be aliased right? – Juan Aug 12 '10 at 16:56
  • Right - C# type aliases only exist at the source code level. In the compiled code, you won't see `AttrValue`, only `object`. – Tim Robinson Aug 12 '10 at 16:58
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Well, the first question is... Why are you using object ?

HTML is text, and therefore all html attributes are strings. You may want to convert them to some other data type (ints or enums), but storing them as objects isn't going to help with that.

James Curran
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If inheritance were a performance issue, .NET would have some major problems. Inheritance is a fundamental concept in C# and it works and performs splendidly. I suggest you create a descendant class and use that. 

public class HtmlAttrValue: System.Object;

If you really wanted to, you can also create a type alias in C#, though not as well as some other languages. A type alias in C# only applies to the file in which it is defined. 

using HtmlAttrValue = System.Object;

This is poorly supported and not very well known and I don't recommend it. You might also find it more convenient to treat your HTML as XHTML (if possible) and use some of the existing XML types and classes to do your work for you.

Phil Gilmore
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  • You can leave off the `: System.Object` from the class declaration since it is implicit. – Corey Ross Aug 12 '10 at 17:17
  • OK, now, if I use `public class HtmlAttrValue: System.Object{}` how do I access the underlying object? I mean, if in my program, right now I do this: ` void SomeFunc(object rawValue) { object attrValue = rawValue; } ` how am I going to do this when `attrValue` is an instance of `AttrValue`? Should I add and `object` field to the `AttrValue` class even though the class is an `object` itself? – Juan Aug 12 '10 at 17:51