where should i initialize collections in the given scenario?

Question

0.00/5 (No votes)

See more:

i have a Dictionary

XML

Dictionary<string, string> Keywords = new Dictionary<string, string>();
Keywords.Add("start", "START");
Keywords.Add("int", "DT");
Keywords.Add("real", "DT");
.
.

this function is in a class and call many times if i define dictionary in it, every time it takes time. so where should i initialize it? if i do this in main() then how can i call it in my class?

C#

public string IsKeyword(string value)
{ 
}

Posted 27-Aug-11 8:00am

Sweety Khan

Add a Solution

3 solutions

Solution 3

Assuming that the keywords are constant, then it makes more sense that the collection is defined at the class level. The previous solutions have already mentioned that. I just want to add that since C#4 (or 3?) it's possible to initialize the collections directly (as sa has already mentioned above).

a complete class would then look as follows:

C#

static class myClass
{
    static Dictionary<string, string> Keywords = new Dictionary<string, string>() 
        {   
            {"start", "START" },
            { "int", "DT" },
            {"real", "DT"}
        };

    public static string IsKeyword(string value)
    { 
        return "???";
    }
}

I'm a bit confused about the signature of the IsKeyword method. for me as a user of the class it doesn't make sense to have a Is... method that returns a string, that's why I left the implementation empty.

Posted 27-Aug-11 20:11pm

Reto Ravasio

Updated 27-Aug-11 20:19pm

v2

Comments

Sweety Khan 28-Aug-11 2:34am

yeh u r right, me realized this toO. i was trying to do 2 things by one method. but now i have made two methods public bool IsKeyword and public string WHichKeyword.

Sweety Khan 28-Aug-11 2:59am

one thing more u said c# 3 or 4 but i dont understand tht how can i know this. i only understand by their names that they are versions and they may have different features. i learned one c# and now working on visualstdio 2010 so whats the story plz tell me

Reto Ravasio 28-Aug-11 3:14am

VS2010 uses C#4 by default but you can tell it to use another version. (Properties/Application/Target framework)

Sweety Khan 28-Aug-11 3:25am

oki thanx a lOt :)

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)

Abhinav S · Accepted Answer · 2011-08-27T08:30:00

Solution 1

Define the dictionary at the class level.

C#

class myClass
{
  Dictionary<string,> Keywords = new Dictionary<string,>();

  public void DictionaryInitializer()
  {
     Keywords.Clear();
     Keywords.Add("start", "START");
     Keywords.Add("int", "DT");
     Keywords.Add("real", "DT");
  }

}

Posted 27-Aug-11 8:30am

Abhinav S

Updated 27-Aug-11 19:21pm

v2

Comments

Sweety Khan 27-Aug-11 15:04pm

gOod idea :) i define the dictionary in myClass constructor. is it fine from time saving and other factors point of view?

Sergey Alexandrovich Kryukov 27-Aug-11 23:41pm

No. Declare at the class level and ***initialize*** where it is declared as Abhinav's code shows. You can also initialize if in constructor, but it makes no sense at all, as initialization does not depend on constructor parameters, previously called methods and anything like that. In this case, initializing at the point of declaration is safer.
--SA

Sergey Alexandrovich Kryukov 27-Aug-11 23:41pm

Sure, my 5.
--SA

Abhinav S 28-Aug-11 1:20am

Thank you SA.

Sweety Khan 28-Aug-11 2:43am

okii i got it. so means before calling IsKeyword method or any i must first call the method DictionaryInitializer().

BillWoodruff · Accepted Answer · 2011-08-27T19:25:00

Of course both Abhinav's and SAK's wise comments point you in the right direction, but let me add one supplementary ... perhaps superfluous ... comment:

Where you initialize the Dictionary depends on its strategic use in the 'total scenario' in your project.

1. if the Dictionary object is part of a class that is instantiated many times, and it is your intent that each instance of the class has a private instance of this Dictionary, obviously the instantiation belongs in the class.

2. if the Dictionary object is a global resource for many classes (forms, whatever), and is invariant, you can consider putting it in a static class, exposing only those methods of access to it you wish, etc. Or, the Dictionary could be defined in a 'Singleton' Class.

best, Bill