ArrayList in C#

Question

Can we pass ArrayLists as arguments to methods in C#?

Answer 1

yes you can.

Answer 2

Sure, why not:

public void SomeMethod(ArrayList list)
{
    // your code here
}

But as Jon S. mentioned using interfaces is preferred instead of hard coded types.

public void SomeMethod(IList list)
{
    // your code here
}

See also:

• Interfaces (C# Programming Guide)
• Generic Interfaces (C# Programming Guide)

Answer 3

Absolutely. However, you rarely should. These days you should almost always use generic types, such as List<T>.

Additionally, when declaring the parameters of a method, it's worth using interfaces where you can. For instance, if you had a method like this:

public void SomeMethod(ArrayList list)

then anyone calling it is forced to use ArrayList. They can't use List<T> even if they want to. If, on the other hand, you declare your method as:

public void SomeMethod(IList list)

then they can use generics even if your code doesn't know about them.

Answer 4

Any Type can be passed as argument of method. Whether abstract one, or interface, or value type, or whatever.

Jon Skeet mention using of interfaces. Yes its good, but have small pitfall - you can not easily navigate from that method to its usage.