More Event Handling...

[John Whitworth]

I'm tying myself up in knots again here.

I think my query is a little different from the previous Event handling one,
so have started a new thread.

In VB2008, I want a reusable control, which can effectively show (and set)
bit settings with true/false descriptions for each byte.

Eventually, I want to group each byte into a panel, so I can treat them as a
whole (and then probably put several panels into a tab control, so that a
3-byte config parameter can be worked on within one form), but for the
moment, I have just added 8 "BitSwitch" controls into a form, the class &
code being as follows:

Public Class BitSwitch

Private _Status As Boolean

Private _TrueDesc As String

Private _FalseDesc As String

Private _BitNo As Integer

Public Sub New(ByVal Status As Boolean, ByVal BitNo As Integer, Optional
ByVal TrueDesc As String = "True", Optional ByVal FalseDesc As String =
"False")

Me.InitializeCo mponent()

Me.RadioPos.Tex t = TrueDesc

Me.RadioNeg.Tex t = FalseDesc

Me.BitLabel.Tex t = "Bit " & BitNo.ToString & ":"

If Status = True Then

RadioPos.Checke d = Enabled

Else

RadioNeg.Checke d = Enabled

End If

End Sub

Public Property BitNo() As Integer

Get

Return _BitNo

End Get

Set(ByVal value As Integer)

_BitNo = value

End Set

End Property

Public Property Status() As Boolean

Get

Return _Status

End Get

Set(ByVal value As Boolean)

_Status = value

End Set

End Property

Public Property TrueDesc() As String

Get

Return _TrueDesc

End Get

Set(ByVal value As String)

_TrueDesc = value

End Set

End Property

Public Property FalseDesc() As String

Get

Return _FalseDesc

End Get

Set(ByVal value As String)

_FalseDesc = value

End Set

End Property

Private Sub RadioPos_Checke dChanged(ByVal sender As Object, ByVal e As
System.EventArg s) Handles RadioPos.Checke dChanged

If RadioPos.Checke d = True Then

_Status = True

Else

_Status = False

End If

' I'm pretty sure I need to fire off my custom event here!!

End Sub

End Class

Public Class TestForm

Private Sub TestForm_Load(B yVal sender As Object, ByVal e As
System.EventArg s) Handles Me.Load

Dim Bit(7) As BitSwitch

Dim CtrlLp As Integer

For CtrlLp = 7 To 0 Step -1

Bit(CtrlLp) = New BitSwitch(True, CtrlLp, "True " & CtrlLp.ToString , "False
" & CtrlLp.ToString )

Bit(CtrlLp).Loc ation = New Point(0, (7 - CtrlLp) * 45)

Me.Controls.Add (Bit(CtrlLp))

Next

End Sub

End Class

So TestForm populates with 8 BitSwitches, and they all show their true/false
descriptions properly. What I want to do is have a custom event that is
fired whenever the state of any of the radio switches is changed in one of
the 8 BitSwitches. Basically, I want an event in TestForm that can
recalculate the byte value based on the settings of the 8 BitSwitches. I
want this to be reusable, as I may want to use the class for several sets of
bit settings at one time.

I looked in the online examples, and started playing with Delegates etc, but
got in a right royal mess! :-) I may well be overengineering this, but I'm
sure this is not simply something that I can do with the GUI.

Thanks

John

[Armin Zingler]

John Whitworth wrote:

What I want to do is have a custom
event that is fired whenever the state of any of the radio switches
is changed in one of the 8 BitSwitches. Basically, I want an event in
TestForm that can recalculate the byte value based on the settings of
the 8 BitSwitches.

1. Class BitSwitch:

Public Event StatusChanged( _
ByVal sender As Object, ByVal NewStatus As Boolean _
)
In Sub RadioPos_Checke dChanged:

RaiseEvent StatusChanged(M e, _Status)

2. Form:
Before "Next":
AddHandler Bit(CtrlLp).Sta tusChanged, AddressOf OnStatusChanged

And a new event handler: (an example)

Private Sub OnStatusChanged ( _
ByVal sender As Object, ByVal NewStatus As Boolean)

MsgBox(DirectCa st(sender, BitSwitch).BitN o & ": " & NewStatus)
End Sub

I want this to be reusable, as I may want to use
the class for several sets of bit settings at one time.

You mean, you need these 8 controls multiple times? Then put them in a
Usercontrol, not directly on the Form. You can add a "Value" property to the
new Usercontrol that returns the calculated value from the 8 bits.
BTW, you don't store all values in Sub New in the usercontrol:

_TrueDesc = TrueDesc
_FalseDesc = FalseDesc
_BitNo = BitNo
And in Sub RadioPos_Checke dChanged, you probably want to update the
displayed text:

If RadioPos.Checke d = True Then
_Status = True
BitLabel.Text = _TrueDesc
Else
_Status = False
BitLabel.Text = _FalseDesc
End If

Armin

[John Whitworth]

"Armin Zingler" <az*******@free net.dewrote in message
news:eX******** ********@TK2MSF TNGP06.phx.gbl. ..

If RadioPos.Checke d = True Then
_Status = True
BitLabel.Text = _TrueDesc
Else
_Status = False
BitLabel.Text = _FalseDesc
End If

Brilliant! Thanks Armin. That all works perfectly. I should be able to move
on a huge amount now. As you suggest, I do need to move this all into
another control, but I just wanted to get something working first in a form.
I don't need to update BitLabel.Text though, as that is just a numeric
label. The way each BitSwitch looks is:

Bit ?: Here is the true description O O Here is the false
description.

Thanks again - it's much appreciated.

John