C# 4 and .NET 4

124 ❘ ChaPTer 5 Generics
The method Swap() defines T as a generic type that is used for two arguments and a variable temp:
void Swap(ref T x, ref T y)
{
T temp;
temp = x;
x = y;
y = temp;
}
A generic method can be invoked by assigning the generic type with the method call:
int i = 4;
int j = 5;
Swap(ref i, ref j);
However, because the C# compiler can get the type of the parameters by calling the Swap() method, it is
not required to assign the generic type with the method call. The generic method can be invoked as simply
as non-generic methods:
int i = 4;
int j = 5;
Swap(ref i, ref j);
generic methods example
Here’s an example where a generic method is used to accumulate all elements of a collection. To show
the features of generic methods, the following Account class that contains Name and Balance properties
is used:
public class Account
{
public string Name { get; private set; }
public decimal Balance { get; private set; }
}
public Account(string name, Decimal balance)
{
this.Name = name;
this.Balance = balance;
}
code snippet GenericMethods/Account.cs
All the accounts where the balance should be accumulated are added to an accounts list of type
List:
var accounts = new List()
{
new Account("Christian", 1500),
new Account("Stephanie", 2200),
new Account("Angela", 1800)
};
code snippet GenericMethods/Program.cs
A traditional way to accumulate all Account objects is by looping through all Account objects with
a foreach statement, as shown here. Because the foreach statement uses the IEnumerable interface
to iterate the elements of a collection, the argument of the AccumulateSimple() method is of type
IEnumerable. The foreach statement works with every object implementing IEnumerable. This way,
the AccumulateSimple() method can be used with all collection classes that implement the interface
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