Is there a type-safe ordered dictionary alternative ?

Question

4.00/5 (1 vote)

See more:

I want to save some pairs in a dictionary.
At the end I want to serialize the dictionary to JSON object.
i then print the Json. I want the pairs to be printed in the same order they were entered to the dictionary.

At first I used an ordinary dictionary. But then I thought the order might not be kept.
Then I migrated to OrderedDictionary but doesn't use Generic, meaning it's not typed-safe.

Do you have any other good-practice solution for me?

Thanks

Posted 23-Mar-11 10:36am

elad2109

Add a Solution

3 solutions

Solution 1

What about SortedDictionary: http://msdn.microsoft.com/en-us/library/f7fta44c.aspx[^].

On the other hand if the instance of your class contains the ordinal, you could use basically any generic collection and before serializing pull out the items in sorted order for example using LINQ, something like (depending on the collection type):

var orderedlist = from item in myDict
                  order by item.Ordinal
                  select item;

Posted 23-Mar-11 10:45am

Wendelius

Comments

elad2109 23-Mar-11 16:51pm

My Values don't have any oridinal or comparer.

1) Generally - How do I implement it?

2) Specific - I want to oreder the Values by thier "Percent" field (decimal value). Is there any "clean" syntax to do so ?

elad2109 23-Mar-11 16:54pm

Can I write:

"order by item.Value.percent"

?

elad2109 24-Mar-11 15:20pm

BTW, how can I define and how do I use a comperator obj in c# (like in java)?
How can I apply LINQ to object to oreder according to that comperator?

Wendelius 24-Mar-11 15:43pm

Don't know Java enough but perhaps these examples would help:
http://msdn.microsoft.com/en-us/vcsharp/aa336756

elad2109 24-Mar-11 17:39pm

Exactly what I was looking 4. 10x !

Wendelius 24-Mar-11 17:51pm

Glad to hear :)

Sergey Alexandrovich Kryukov 23-Mar-11 18:27pm

If you don't have the comparer, is simply say the part of your requirement "ordered" makes no sense.
Just be logical. Please see my Answer.
--SA

Wendelius 23-Mar-11 16:55pm

So if you want to sort the items by the decimal value then you would use that property (or field) in the order by clause:
...
order by item.Percent
select item;

elad2109 23-Mar-11 16:57pm

It's more complex object:

Pair<key,value> ==> <string, dataclass=""> ==> <string, <decimal,="" list...="">>

Can I still use LINQ ?

Wendelius 23-Mar-11 17:04pm

I don't see why not. If you're using nested collections with native data types (if I understood the description correctly) you could consider creating entity like classes to hold the values and to store into the collection (if not already done so).

elad2109 23-Mar-11 17:22pm

I have a dictionary of

<string, <decimal,list<mytype="">>>

So the right syntax would be:
"order by item.Value.decimalfield"

?

Wendelius 23-Mar-11 17:28pm

If I remember correctly, yes (can't check that right now). One good thing with LINQ is that the intellisense usually works fine so it assists you when writing a query.

elad2109 23-Mar-11 17:38pm

10x, I'll try tomorrow

Sergey Alexandrovich Kryukov 23-Mar-11 18:28pm

I voted 5 even though it looks like OP has nothing to "sort" (so see my Answer).
I voted 5 because you did not know that before the discussion.
--SA

Solution 3

If your key/values are not ordered, I think what you need is the most used generic class System.Collections.Generic.Dictionary<TKey, TValue>. I also think you never need obsolete none-generic collections.

—SA

Posted 23-Mar-11 12:25pm

Sergey Alexandrovich Kryukov

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Accepted Answer · 2011-03-23T10:47:00

Solution 2

Here at CodeProject there is an article about: "OrderedDictionary<t>: A generic implementation of IOrderedDictionary"[^]

Posted 23-Mar-11 10:47am

CPallini

Comments

Wendelius 23-Mar-11 16:49pm

Good link, +5.

elad2109 23-Mar-11 16:53pm

I saw this before. I prefer .net type. If I find no such I might use that. Thanks