Help with Hashtable Iteration

[Hinder]

Ok, I have always been able to iterate though a hashtable with the "Option Strict turned Off" but after someone suggesting I should code with it ON for good practice reasons, Now I'm running into problems Iterating though a Hashtable that I store a Class object in..

The old way worked fine..

        Dim en As IDictionaryEnumerator = HashTest.GetEnumerator

        With lstID
            .BeginUpdate()
            .Items.Clear()
            While en.MoveNext
                Dim R As clsTest = en.Value
                .Items.Add(R.MyID)
            End While
            .EndUpdate()
        End With

Now that I have turned Option Strict on, it bugs out, I get an error that says..

Option Strict On disallows implicit conversions from 'System.Object' to 'Hashing.clsTest'.

which applies to this:

Dim R As clsTest = en.Value

I have tried to cast it by doing

Dim R As clsTest = CType(en.Value, clsTest)

But it won't let me cast it to that class type..

Does anyone know what I need to do in order to do this?

[powdir]

this any help...

        Dim ht As New Hashtable()
        '
        ht.Add("1", New clsTest("OBJECT 1"))
        ht.Add("2", New clsTest("OBJECT 2"))
        '
        Dim di As DictionaryEntry
        Dim o As clsTest
        '
        For Each di In ht
            o = DirectCast(di.Value, clsTest)
            With Me.ListBox1
                .Items.Add(o.MyID)
            End With
        Next
        '

...PS I overloaded the constructor of your clsTest to accept some string values

[Hinder]

Thanks... Funny thing is once I rebooted and tried that same code again, it worked fine... Go Figure huh....

Anyways I didn't want to start a new thread about the same topic so I want to extend on this question and add a second part to it..

Now that I got the Iteration working, I'm faced with a new problem.. I am not just storing one special class in the hashtable but instead I have 3 different classes I am storing in the hashtable..

Say I have:

Class1
Class2
Class3

Now there is no logical order they are stored in the hashtable.. so I need to know how to identify the class that I am casting when iterating through a hashtable...

so how do I identify this:

        For Each di In ht
            o = DirectCast(di.Value, clsTest)
            With Me.ListBox1
                .Items.Add(o.MyID)
            End With
        Next

The di.Value can be one of 3 classes so I need to figure out what "o" should be before I can cast "di.value" to it, how do I do this?

[powdir]

Could use the generic o.getType.toString and a few case statements but this example cries out for a common interface shared among your three classes. That way you could cast whatever your hashtable contains to the interface type without much worry. See the revised code

   Dim ht As New Hashtable()
        ht.Add("1", New clsTest("CLASS TEST 1"))
        ht.Add("2", New clsTest2("CLASS TEST 2"))

        Dim di As DictionaryEntry
        Dim o As clsCommon
        For Each di In ht
            o = DirectCast(di.Value, clsCommon
            With Me.ListBox1
                .Items.Add(o.MyId)
            End With
        Next

[Hinder]

Could use the generic o.getType.toString and a few case statements but this example cries out for a common interface shared among your three classes.

Ok this sounds interesting, would you mind touching a bit deeper on these "interfaces"? I am a VB6 migrater and .Net is still pretty new to me.. I have heard of "interfaces" but haven't gotten my hands dirty or seen them in use for that matter.. Thanks...

[powdir]

Interfaces (to a degree!) are available to the VB6 programmer - but for semantics and a bit of VB.NET syntax check out:

http://msdn.microsoft.com/library/de...interfaces.asp

i get the impression that your 3 classes have a good deal in common. If that IS the case think about using the above in your app. Try and factor the methods/properties that are shared to an interface, but don't shoehorn classes to fit with an interface if they clearly dont belong.

I s'pose the concept is similar to using one of those 'all in one' TV/satellite/stereo remotes in that it [the remote control] provides a common set of buttons to operate on the various devices.

HTH