Indexers are great, I've only really started using them consciously today, but they're a great discovery I'll be sure to incorporate into more of my code from now on.
As you can see here, we have a class, but we access a value as if it was an array, or a Hashtable. Just think of how you could use this!
VarClass vc = new VarClass();
vc["key"] = "value";
Console.WriteLine(vc["key"].ToString());
The code is really simple too, it's simply like a property with an input, here we just put a layer on top of a Hashtable, you can of course add something more useful, but this shows you how it works:
class VarClass
{
private Hashtable ht = new Hashtable();
public object this[object key]
{
get
{
return ht[key];
}
set
{
ht[key] = value;
}
}
}
As you can see, you take the object they put within the square brackets as a parameter, and you make a property but as the name you put the keyword this, referring to the actual class object.
I just think it's so simply, yet so awesome..
I actually came across this whilst writing a simple Hashtable clone for someone over at Dream.In.Code. For the sake of your dying curiosity I will post the awesome class here:
class HashtableEx
{
private List<object> keys = new List<object>();
private List<object> values = new List<object>();
public object this[object key]
{
get
{
int index = keys.IndexOf(key);
if (index == -1) return null;
else return values[index];
}
set
{
if (keys.Contains(key))
{
int index = keys.IndexOf(key);
values[index] = value;
}
else
{
keys.Add(key);
values.Add(value);
}
}
}
public object Get(object key)
{
int index = keys.IndexOf(key);
return values[index];
}
public void Add(object key, object value)
{
keys.Add(key);
values.Add(value);
}
public void Remove(object key)
{
int index = keys.IndexOf(key);
keys.RemoveAt(index);
values.RemoveAt(index);
}
public void Clear()
{
keys = new List<object>();
values = new List<object>();
}
}
Use it like so:
static void Main()
{
HashtableEx ht = new HashtableEx();
ht["hello"] = "world";
Console.WriteLine("Value of \"hello\": {0}", ht["hello"]);
Console.WriteLine("Type of \"hello\": {0}", ht["hello"].GetType());
Console.ReadKey();
}
Which gives you the output:
Value of "hello": world
Type of "hello": System.String
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