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Switch statement alternative

, 22 Jul 2014 CPOL
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switch statement alternative using anonymous code

Background

Switch statement alternative using Func type

Using the code

You can use a Dictionary to create a mapping of Condition => Action.


class Programm
{
    static void Main()
    {
        Func<int, bool> Default = (x=> true);
        
        var myNum = 1200;
        var cases = new Dictionary<Func<int, bool>, Action>
        {
            { x => x < 3 ,    () => Console.WriteLine("Smaler than 3")   } ,
            { x => x < 30 ,   () => Console.WriteLine("Smaler than 30")  } ,
            { x => x < 300 ,  () => Console.WriteLine("Smaler than 300") },
            { Default,        () => Console.WriteLine("Default case") }
        };
        
        cases.First(kvp => kvp.Key(myNum)).Value();
    }
}

This technique is not a general alternative to switch statement.

Suppose you have a workflow system that is required to perform validation of a data item. Different validation routines are executed based upon some state of the data being processed. Using this technique means
a) You do not have a switch statement with over 100 case statements - very difficult to read.
b) You do not have to include conditional logic in the case statement for each validation routine - very difficult to maintain.
c) You can offload the validation routines and conditional logic into a database where the customer can then update when a validation routine executes as per their requirements - very flexible.

 

 

Thanks for the comments @John B. Oliver

License

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

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About the Author

Nitin Sawant
Software Developer (Senior)
India India
I’m a .NET Developer working for a private IT firm, I love the creative software development process and each completed project causes me to be more daring and inspired to reach a new threshold in terms of design and development:
 
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Comments and Discussions

 
SuggestionAnother valid case PinmemberTomas Ruksenas20-Aug-14 22:31 
GeneralMy vote of 1 Pinmemberahagel23-Jul-14 19:06 
GeneralRe: My vote of 1 PinmemberJohn B Oliver24-Jul-14 13:07 
GeneralRe: My vote of 1 Pinmemberahagel24-Jul-14 14:32 
QuestionWhat about letting the compiler do its magic on switch statements? PinmemberFrederico Barbosa22-Jul-14 23:51 
AnswerRe: What about letting the compiler do its magic on switch statements? PinprofessionalNitin Sawant23-Jul-14 3:54 
GeneralRe: What about letting the compiler do its magic on switch statements? PinmemberFrederico Barbosa29-Jul-14 2:49 
QuestionCan't Linq be used here? PinmemberGeorge Swan22-Jul-14 22:02 
AnswerRe: Can't Linq be used here? PinprofessionalNitin Sawant23-Jul-14 3:55 
GeneralMy vote of 1 PinprofessionalDan Colasanti21-Jul-14 12:41 
GeneralRe: My vote of 1 PinprofessionalNitin Sawant23-Jul-14 3:57 
GeneralRe: My vote of 1 PinmemberFatCatProgrammer23-Jul-14 6:53 
GeneralRe: My vote of 1 PinprofessionalDan Colasanti23-Jul-14 8:22 
GeneralRe: My vote of 1 PinmemberJohn B Oliver24-Jul-14 13:23 
GeneralRe: My vote of 1 PinprofessionalDan Colasanti24-Jul-14 17:05 
Questionquestion PinprofessionalSimon_Whale21-Jul-14 4:41 
QuestionWouldn't this be an if ... else rather than a switch? PinmemberPeejayAdams21-Jul-14 4:33 
QuestionA List is better in this case. PinprofessionalPaulo Zemek18-Jul-14 5:52 
AnswerRe: A List is better in this case. PinmemberMember 1058457421-Jul-14 2:24 
GeneralRe: A List is better in this case. Pinmemberleppie21-Jul-14 2:31 
AnswerRe: A List is better in this case. PinmemberJames Curran21-Jul-14 3:09 
QuestionYou need a default case PinmemberJames Curran18-Jul-14 5:29 
AnswerRe: You need a default case PinprofessionalNitin Sawant20-Jul-14 20:42 

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