Tip: how to simplify value access from a dictionary ? With an extension method !

I was getting really bored with testing .ContainsKey() at each time I wanted to read a value from a dictionary.

 Dictionary<string, string> dico;
if (dico.ContainsKey("key"))
    value = dico["key"];
else
    value = "default";

A incredibly simple extension method solves this so easily:

 public static class MyExtensions
{
    public static TValue GetValue<TKey, TValue>(
        this IDictionary<TKey, TValue> source,
        TKey key, TValue defaultValue)
    {
        if (source.ContainsKey(key))
            return source[key];
        else
            return defaultValue;
    }
}

The call from any dictionary now becomes:

 value = dico.GetValue("key", "default");

...sometimes I just wonder how I did not think about such solutions earlier ! :-)

Comments

• Anonymous
  May 07, 2008
  PingBack from http://dictionary.azzblog.info/?p=2354

• Anonymous
  May 07, 2008
  You can optimise this slightly further by using TryGetValue... :)

• Anonymous
  May 07, 2008
  public static class MyExtensions {    public static TValue GetValue<TKey, TValue>(        this IDictionary<TKey, TValue> source,        TKey key, TValue defaultValue)    {        TValue result;        return source.TryGetValue(key, out result) ? result : defaultValue;    } }

• Anonymous
  May 07, 2008
  Funy Mitsu ! I do the same for Request Params.

• Anonymous
  May 10, 2008
  Thanks for the TryGetValue modification. It is much better using it. The extension method still brings an easier syntax, allowing to be used inside an expression.

• Anonymous
  May 22, 2008
  Yet another variation. public static TValue        GetValue<TKey, TValue>(this IDictionary<TKey, TValue> source, TKey key) {   TValue result;   return source.TryGetValue(key, out result) ? result : default(TValue); }