I want to return an ArrayList from my web service. I can write this part and
everything compiles but I can't get the web application that uses the web
service to compile. I call the service aynchronously so then in my code I
have this to retrieve the ArrayList object.

public void CalcCallback(IAsyncResult ar)
{
   ArrayList arrResults = ws.MyFunction(ar);
}

If I try to compile this I get an error

Cannot implicitly convert type 'object[]' to 'System.Collections.ArrayList'

Any idea how I can fix this? I found a sample web service on MDSN that
returned an ArrayList but it doesn't include the client app to go with it.