Visual Basic

11-Feb-12 0:41

Hello everybody,

I have a child form which is supposed to show an exact duplicate of a part of the main form including its controls - here I'm in particular speaking about a ComboBox. What I'm trying to accomplish is that the user can either change a setting on the main form's ComboBox or on the child forms ComboBox to have both forms update the underlying list of a Datagridview as well as the ComboBox/Datagridview on the other form.

Is there any 'best practices' way of synchronizing controls on two forms? I would surely have to avoid firing events twice (e.g. combo updated by user would update the corresponding combo on the other form and fire again).

Thanks for advice,
Mick

Luc Pattyn11-Feb-12 2:17

11-Feb-12 2:17

AFAIK you can achieve that by using simple data binding:
- create a small class describing each item, with at least two properties (e.g. string Display, and int Value);
- store your items in a generic List;
- for both ComboBoxes set the DataSource to that list, and the DisplayMember and ValueMember to the names of the relevant properties. The DisplayMember is what will be shown, the ValueMember what will be returned as the SelectedValue.

With both ComboBoxes set up identically, they will act like one, i.e. fully synchronized; however each of them will fire its events. So you can deal with each of them as if the other didn't exist.

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.

modified 11-Feb-12 8:57am.

Sonhospa11-Feb-12 15:18

11-Feb-12 15:18

Hi Luc,

sorry for my late response, I had to find the time to figure that out and still find myself stuck.

Following your advice I defined the class "AirportRange"

Public Class AirportRange
	Private _display As String
	Public Property Display() As String
		Get
			Return _display
		End Get
		Set(ByVal value As String)
			_display = value
		End Set
	End Property

	Private _value As Integer
	Public Property Value() As Integer
		Get
			Return _value
		End Get
		Set(ByVal value As Integer)
			_value = value
		End Set
	End Property
End Class

Storing the class in a generic list didn't work (e.g. I didn't know how to), so I used the designer and set up the class as a Project DataSource - after which VS creates an "AirportRangesBindingSource" from it. This I used as DataSource for the new comboBoxes on my main and child forms, setting DataMember and ValueMember to the properties as you suggested.

A problem arose: The forms show, but I can't define items for them - which results in no possibility to select any values from the ComboBox. The items obviously have to be defined in the class istself? At least when I open the "items" property, I get an error message saying it wouldn't be possible to set items as a DataSource is defined...

Can you help me out of that?
Thanks for now,
Mick

Luc Pattyn11-Feb-12 15:47

11-Feb-12 15:47

You should keep things simple, especially when you don't understand them well.
And not knowing the basics of generic lists is not acceptable nowadays!

Here is a demo class to describe the combobox items:

Public Class Item
    Private myValue As Integer
    Private myName As String

    Public Sub New(ByVal number As Integer, ByVal name As String)
        myValue = number
        myName = name
    End Sub

    Public ReadOnly Property Valu() As Integer
        Get
            Return myValue
        End Get
    End Property

    Public ReadOnly Property Name() As String
        Get
            Return myName
        End Get
    End Property
End Class

and this could be part of a Form that holds a number of comboboxes, all showing the same list, and working fully synchronized:

Private Items As List(Of Item)

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Items = New List(Of Item)
    Items.Add(New Item(1, "one"))
    Items.Add(New Item(2, "two"))
    Items.Add(New Item(3, "three"))
    For Each ctrl As Control In Me.Controls
        If TypeOf (ctrl) Is ComboBox Then
            Dim cmb As ComboBox = CType(ctrl, ComboBox)
            cmb.DataSource = Items
            cmb.DisplayMember = "Name"
            cmb.ValueMember = "Valu"
        End If
    Next
End Sub

That is all there is to it. No magic, no wizards involved.

PS: when you attach a SelectedValueChanged handler to each ComboBox, you'll see they all fire, the one you actually changed fires first, then the others in arbitrary order.

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.

Sonhospa11-Feb-12 23:36

11-Feb-12 23:36

Actually I had built this solution (a custom control in connection with a custom 'changed' event both forms shared) before and discarded it – thinking your suggestion would show a completely different approach – because ... this approach only solves a part of my problem, raising another one:

Having every control fire it's changed events I end up actualizing the underlying lists twice (which is time intensive)! I had first tried to avoid that by identyfying the clicked control (passing the sender to the FindForm function), but there' obviously no difference between the index change by a 'real user selection' and a remote index change triggered by the other control's changed-event. Could that effect be avoided?

Regards
Mick

Luc Pattyn12-Feb-12 0:04

12-Feb-12 0:04

you could use a global variable GlobalVal to hold the current value of your synchronized comboboxes.
in each SelectedValueChanged handler, compare the new value to GlobalVal; when different do everything that needs to be done and update GlobalVal, when equal do less (or even nothing at all).

Which basically means you would be using a cache with just one entry.

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.

Sonhospa12-Feb-12 1:35

OLE Automation error 438 when registering a XLL using custom action

12-Feb-12 1:35

Wow - you seem to be online day and night Java | [Coffee]

And yes, that makes sense and keeps it simple, too Wink | ;)

I'm going to check that out.

Thank you in advance Cool | :cool:

Mick

tagad10-Feb-12 6:17

tagad

10-Feb-12 6:17

Hi,

I would like to register an XLL while installing a project using MSI.

I am using a VB.NET installer class to do this:

Imports System.ComponentModel
Imports System.Configuration.Install
Imports System.ArgumentException
Imports Microsoft.Office.Interop

Public Class Installer1

    Public Overrides Sub Install(ByVal stateSaver As System.Collections.IDictionary)
        MyBase.Install(stateSaver)

        Dim targetDir = Me.Context.Parameters.Item("targetdir")
        targetDir = targetDir.Substring(0, targetDir.Length - 1)
        MsgBox(targetDir)

        Dim myScript = targetDir + "MySuperAddin.xll"
        MsgBox(myScript)

        Dim objAddin As Object
        Dim objEXL As Excel.Application = DirectCast(CreateObject("Excel.Application"), Excel.Application)

        objEXL.Workbooks.Add()
        Try

            objAddin = objEXL.AddIns.Add(myScript, True)
            objAddin(myScript).Installed = True

        Catch ex As Exception
            MsgBox("cannot open addin. /n Error: " + ex.Message)
Err_Handler:
            MsgBox(Err.Description, vbCritical, "Error: " & Err.Number)
        End Try
        objAddin = Nothing
        objEXL.Quit()
        objEXL = Nothing
    End Sub
End Class

When I run this code as a VB script on my desktop I dont have any issue.

it is a very standard way to install an addin

please see the link
http://stackoverflow.com/questions/1130301/uninstalling-excel-add-in-using-vbscript[^]

However when I run it during the installation I get

Error: 438 Member not found. (Exception from HRESULTS: 0x80020003 (DISP_E_MEMBERNOTFOUND))

I tried to find a solution using the following links:
1) http://support.microsoft.com/kb/172108[^]

and

2) http://support.microsoft.com/kb/213489/[^]

but NO success. it is a clear problem with OLE Automation Object. I would really appreciate a suggestion. MANY THANKS!!

How do I check programmatically if installed version of ACE OleDb is 64 or 32 bit version?

Jörgen Andersson9-Feb-12 22:33

Jörgen Andersson

9-Feb-12 22:33

My Google foo is failing me.

Light moves faster than sound. That is why some people appear bright, until you hear them speak.
List of common misconceptions

Re: How do I check programmatically if installed version of ACE OleDb is 64 or 32 bit version?

Luc Pattyn9-Feb-12 23:36

Re: How do I check programmatically if installed version of ACE OleDb is 64 or 32 bit version?

9-Feb-12 23:36

IIRC a 64-bit version of the OleDb data provider doesn't exist.

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.

Jörgen Andersson9-Feb-12 23:47

Jörgen Andersson

9-Feb-12 23:47

Well, it does.[^]
And normally I would be happy about that, but at the moment it's a bit of a problem to solve.

Light moves faster than sound. That is why some people appear bright, until you hear them speak.
List of common misconceptions

Re: How do I check programmatically if installed version of ACE OleDb is 64 or 32 bit version?

Luc Pattyn9-Feb-12 23:59