problem with objects

[nswan]

Hi,

i have the following class

Public Class room
    Public roomID As Integer
    Public hotelID As Integer
    Public size As String
    Public singleDouble As String
    Public enSuite As Boolean
    Public cost As Integer
    Public description As String
End Class

and the next class makes a collection of rooms

Public Class rooms
    Private mcolRooms As New Collection()

    'add a room to our collection
    Public Sub add(ByVal room As room, ByVal key As String)
        mcolRooms.Add(room, key)
    End Sub

    'return the number of rooms in our collection
    Public ReadOnly Property Count() As Integer
        Get
            Return mcolRooms.Count
        End Get
    End Property

    'return a room object from our collection
    Public ReadOnly Property Item(ByVal IndexOrKey As Object) As room
        Get
            Return mcolRooms.Item(IndexOrKey)
        End Get
    End Property

End Class

the problem i have is that i am trying to check to see if a room has been added to the collection already. This would be checked by the roomID(which is added as a key when the add procedure is used). Is there an easy way or do i have to loop through the collection and check each room to see if it exists?

Thanks
Nick

[Edneeis]

Well if you are using the collection object then there is no intrinsic way of finding out whether the item is there or not. A lot of the other collection variants can though. Or if you don't want to switch that then you can use error handling to find out the quick way.

Private Function ContainsKey(ByVal col As Collection, ByVal key As String) As Boolean
        Try
            Dim o As Object = col.Item(key)
        Catch
            Return False
        End Try
        Return True
    End Function

[nswan]

Thanks Edneeis,

that worked a treat. What are the other types of collections you mentioned though?

[Edneeis]

Check in the help under the System.Collection namespace there are quite a few: SortedList, Hashtable, Dictionary, NameValueCollection...