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String.Format

In Microsoft.Net most of the objects implement .ToString() function. This is a very powerful function which returns
string representation of underlying object. However if it is overused with concation operators like + in C#, it can
have serious performace hit for large application. The problem with concatenation is that it create a new string
for every concatenation operator and assigns memory to it. If it is just string concatenation you are looking
for, use StringBuilder class instead.

A better and Microsoft recomended way of formatting strings is to use String.Format.
This is a very powerful funation and you would be amazed by the number of formats it support. Once you get hang
of it, you will never go back to using .ToString.

Here is an example. Say you wany to display current date time. Your normal code would be

Response.write("Todays Date is: " + DateTime.Now.ToString("dd/MM/YYYY"));

A better way would be

Reponse.Write(String.Format("Todays Date is:{0:dd/MM/YYYY}",DateTime.Now))

For a detailed list of formattinfg see
http://msdn.microsoft.com/en-us/library/aa302329.aspx
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