Make Extension method on base class .NET

Question

Possible Duplicate:
Static extension methods

So I know that Extension methods are for object instances only as in doing

public static string stringBig(this string inString) {
     return inString.ToUpper();
}

Only works for an instance of string

However I am trying to make something that function like Double.TryParse so that I don't have to do

Double myDouble = someOtherDouble.DoubleParseDifferent("4.324802348203498");

I'd like to be able to do something like

Double myDouble = Double.DoubleParseDifferent(someRandomString);

Now I know that I can't actually do this so what would be some alternative methods or ways I could approach this.

Possible dupe http://stackoverflow.com/questions/866921/static-extension-methods — Brook, Jan 05 '11 at 20:19
@Brook yes it is a dupe, I looked forever and didn't find that question. Thanks :) — msarchet, Jan 05 '11 at 20:23

score 3 · Answer 1 · answered Jan 05 '11 at 20:17

3

You can make a class with a similar name:

static class MyDouble { ... }

answered Jan 05 '11 at 20:17

SLaks

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score 2 · Accepted Answer · answered Jan 05 '11 at 20:35

The only possible alternative way for implementing TryParse I can think of (since what you're asking for is not possible) would be creating a normal static method, but returning a nullable.

public static double? TryParseEx(string value) { /* new improved parse code here */ }

var result = TryParseEx("1234.56");

That way you would not need a output parameter like the normal TryParse...

If !result.HasValue, then the parse was not successful. Otherwise, just read the result.Value property to get the parsed result.

hmmm this may be the style of thought I may go for doing this. I know what I was asking for wasn't possible which is why I wanted some other way. — msarchet, Jan 05 '11 at 21:04

score 1 · Answer 3 · answered Jan 05 '11 at 20:20

1

Since you're adding a string parsing method, why not add an extension to string

public static Double ParseDifferent( this string inString) {
     return ...
}

answered Jan 05 '11 at 20:20

Paul Alexander

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It was all just example typeage, but like Double.Parse – msarchet Jan 05 '11 at 20:22
Still, adding a Parse method to the source type makes sense. Otherwise your own static MyDouble class as @SLaks mentions is the best bet. – Paul Alexander Jan 05 '11 at 21:03

Make Extension method on base class .NET

3 Answers3