Adding to a collection in Net vs VB6 ...

[Mike]

Checking whether an item exists in a collection before adding it ... (Key is
always a string and in this case is the value as well)

As Net has a Contains method ... is the following a safe alternative to the
VB6 On Error Resume Next?

If Not colDs.Contains(sKey) Then
colIDs.Add(sKey, sKey)
End If

Thanks,
Mike

 

[Tom Shelton]

Checking whether an item exists in a collection before adding it ... (Key is
always a string and in this case is the value as well)

As Net has a Contains method ... is the following a safe alternative to the
VB6 On Error Resume Next?

If Not colDs.Contains(sKey) Then
colIDs.Add(sKey, sKey)
End If

Thanks,
Mike

Well, assuming this is a Dictionary (Of String, Of String) you would
use:

If Not colDs.ContainsKey(sKey) Then
....
End If

And if it's a System.Collections.Hashtable - then the code is the same

 

[Cor Ligthert[MVP]]

Mike,

In VB6 you have one collection (which is as well in VB for Net and not in
C#). However most of us here have the opinion that it is the only thing that
should be as possible avoided from the Net namespace Microsoft.VisualBasic
(this is a true part of Net).

In .Net there are endless collections, lists, special collections, generic
collections etc.

In this case you can start with the arraylist, however better is a simple
List(of String) because then the strings are easier to use.

http://msdn2.microsoft.com/en-us/library/6sh2ey19(vs.80).aspx

Cor

 

[kimiraikkonen]

With .NET 3.5 Linq queries were added as feature. Maybe you can
benefit:

Linq to objects is used for your object (string):
http://www.hookedonlinq.com/LINQtoObjects.ashx

 

[Mike]

Thanks very much for all the replies.

The code which I'm converting from VB6 uses a number of simple collections
and the On Error Resume Next statement to handle duplicate keys. As I'm sure
you know, this was a common VB6 practice.

What I was wondering is whether the Net methods Contains/ContainsKey are
regarded as a safe alternative to the Resume Next error handling. It seems a
little too simple, so I was wondering if I'm missing some gotcha here ...

 

[Cor Ligthert[MVP]]

Mike,

The Resume next has *seldom* been a good handling of known situations
(As the try and catch are as well not).

The one you use now is preventing not wanted situations, whereabout you have
full control.

Cor

 

[Mike]

Absolutely agree with you.

Thanks again,
Mike