asp.net mvc - a default value for a Dictionary in c# -

this question has answer here:

• is there idictionary implementation that, on missing key, returns default value instead of throwing? 9 answers
• dictionary returning default value if key not exist [duplicate] 4 answers

i have following pageviewmodel class:

public class pageviewmodel : viewmodel<page> {  public pageviewmodel ()         {             kywords = new list<keyword>();             answserkeyworddictionary = new dictionary<string, answer>();         }         public company company { get; set; }         public list<keyword> kywords { get; set; }         public dictionary<string, answer> answserkeyworddictionary { get; set; } } 

in view i'm using property answserkeyworddictionary that:

@html.displayaffirmativeanswer(model.answserkeyworddictionary["mykey"]) 

my question : how can return default value if "mykey" not in dictionary.

thanks in advance

check if exists, if not, return default value:

model.answserkeyworddictionary.containskey("mykey")     ? model.answserkeyworddictionary["mykey"]     : "default" 

you create extension method that:

    public static dictionary<k, v> getvalueordefault<k, v>(this dictionary<k, v> dictionary, k key, v defaultvalue)     {         v val;         if (dictionary.trygetvalue(key, out val))         {             return val ?? defaultvalue;         }          return defaultvalue;     } 

use this:

model.answserkeyworddictionary.getvalueordefault("mykey", "default")