Question

I have an abstract base class that holds a Dictionary. I’d like inherited classes to be able to access the dictionary fields using a convenient syntax. Currently I have lots of code like this:

string temp;
int val;
if (this.Fields.TryGetValue("Key", out temp)) {
    if (int.TryParse(temp, out val)) {
        // do something with val...
    }
}

Obviously I can wrap this in utility functions but I’d like to have a cool, convenient syntax for accessing the dictionary fields where I can simply say something like:

int result = @Key;

Is there any way to do something like this in C# (3.5)?

Answer 1

You could add an indexer to your class and pass the indexer’s parameter through to the dictionary.

class Foo
{
    // Initialized elsewhere
    Dictionary<String,String> Fields;

    public Int32 this[String key]
    {
        String temp = null;
        Int32 val = 0;
        if (this.Fields.TryGetValue(key, out temp)) {
            Int32.TryParse(temp, out val);
        }
        return val;
    }
}

Then given an instance of Foo called foo you could do this:

Int32 value = foo["Key"];