Help with Hashtable Iteration

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..

Code:

---

        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:

Code:

---

Dim R As clsTest = en.Value

---

I have tried to cast it by doing

Code:

---

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?

this any help...

Code:

---

        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

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:

Code:

---

        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?

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

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

---

Quote:

---

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...

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