I was trying to convert c# code to vb.net.It is actually inheriting a class from arraylist
How can i convert these lines to vb.net
public new UserInfo this[int index]
{
get
{
return (UserInfo)base[index];
}
}
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Base is the underlying Array list and userinfo is the custom class i defined
this is the full code
public class RUserInfoList : ArrayList
{
#region Constructor
/// <summary>
/// Constructor
/// </summary>
public RUserInfoList() : base()
{
}
#endregion
public new UserInfo this[int index]
{
get
{
return (UserInfo)base[index];
}
}
#endregion
}
}
These are my doubts
public new UserInfo this[int index]->what is this line doing.Why new is used and the new is not in the vb code?
How this line-> return (UserInfo)base[index];->be
Do we need MyBase.Item(index) or just mybase(index) will do?
Thanks
Joe
your 2nd question:
(UserInfo) base[index] => Return CType(MyBase.Item(index), UserInfo)
the leading (UserInfo) is casting (or converting) base[index] into that type.... this is done in VB.NET using CType
and you probably could use mybase(index) ... but i personally think it's clearer when reading to use MyBase.Item(index)... the reason why both work is that item is the default property I think
The new keyword there is like the vb.net keyword "Shadows" It means that since the indexer returns a different datatype, you must shadow or hide the method rather than a true override...
So strictly speaking (and I think the compiler might insist on this anyway) the translation should be:
Public Shadows ReadOnly Property Item(ByVal Index As Integer) As UserInfo
Get
Return CType(MyBase.Item(Index), UserInfo)
End Get
End Property
>I might be wrong, but I think VB.NET returns a new instance of an object when using a function, or get method (which is practically a function)<
Either vb.net or C# will return Nothing or Null respectively unless you explicitly use the New keyword to allocate a new object. Note that in C# the new keyword has double use:
http://msdn.microsoft.com/
What I was trying to get at was why there isn't a New keyword in the method "heading"... i.e. it's not like this in VB.NET
Function New Farenheit(ByVal Celsius As Integer) As Integer...
that's who i took the question about why Vb.NET doesn't have the New keyword in it :P ... it could be taken different ways i guess
Business Accounts
Answer for Membership
by: S-TwilleyPosted on 2005-03-10 at 13:14:48ID: 13510890
I'm assuming UserInfo is some class you designed :|
I can't be sure about this, as I don't know where the base array is declared... but something like this I think:
ReadOnly Property this(ByVal index As Integer) As UserInfo
Get
Return base(index)
End Get
End Property
===============
If base is the underlying ArrayList item collection... and your property is just casting the items then:
===============
Public Class myArrayListClass
Inherits ArrayList
'...
'This is the bit that probably interests tiy
ReadOnly Property this(ByVal index As Integer) As UserInfo
Get
Return CType(MyBase.Item(index), UserInfo)
End Get
End Property
End Class
============
If I've misundestood... could you give a bit more info