Question

I want to create an object that will work in a similar way to ASP.Net Session.

Say I call this object mySession, I want to make it so when you do

mySession["Username"] = "Gav"

It will either add it to a database table if it doesnt exist or update it if it does. I can write a method to do this but have no idea how to get it to fire when used with the indexer syntax ([]). I’ve never built an object that does anything like this with indexers.

Before anyone says anything I know the ASP.Net session can save to database but in this case I need a slightly simpler customized solution.

Any pointers or examples of using indexers in this way would be great.

Thanks

Answer 1

It’s actually pretty much the same as writing a typical property:

public class MySessionThing
{
    public object this[string key]
    {
        //called when we ask for something = mySession["value"]
        get
        {
            return MyGetData(key);
        }
        //called when we assign mySession["value"] = something
        set
        {
            MySetData(key, value);
        }
    }

    private object MyGetData(string key)
    {
        //lookup and return object
    }

    private void MySetData(string key, object value)
    {
        //store the key/object pair to your repository
    }
}

The only difference is we use the keyword “this” instead of giving it a proper name:

public          object            MyProperty
^access         ^(return) type    ^name
 modifier

public          object            this
^ditto          ^ditto            ^ "name"