Private Sub cboItemName_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboItemName.SelectedIndexChanged
     '-- Look the item price and if found and there is a current price, ask
     ' the user if he/she wants to overwrite the Item Price.
     If Me.BizItems_Lookup.Count > 0 Then
          If Me.BizItems_Lookup.SeekToPrimaryKey(Me.bizSC_AppliancesItems1.FK_Items) Then
               If Me.bizSC_AppliancesItems1.ItemPrice <= 0 Then
                    Me.bizSC_AppliancesItems1.ItemPrice = Me.BizItems_Lookup.ItemPrice
               Else
                    If Me.ShowMessageByKey("ApplianceItems_OverwriteItemPrice", Me.bizSC_AppliancesItems1.ItemPrice, Me.BizItems_Lookup.ItemPrice) = MicroFour.StrataFrame.Messaging.MessageFunctionType.Yes Then
                         Me.bizSC_AppliancesItems1.ItemPrice = Me.BizItems_Lookup.ItemPrice
                    End If
               End If
          End If
          Me.bizSC_AppliancesItems1.Refresh("ItemPrice")
     End If
End Sub

The problem is that when the ChildFormDialog is being loaded, the cboItemName_SelectedIndexChanged method is being fired several times, even when the form has not even shown.  In VFP I would simply put the code in the combobox.Valid(), how to get the same effect as the VFP combobox.Valid() or what event should be used in the combo in this scenario ?

I have had exactly what you are talking about in the past. To overcome it I have created a form level boolean variable that I set to true at the start of the form load, then false when the form load is over.

Then in my various events that fire during the form load, such as the one you describe, I put the line

IF _IsLoading = true then exit sub

---- THE GOTCHA

This method has worked for me in some place, and come back and bitten me in others.

What might work better, and I have done this also, is if your combo box is bound to a BO, maybe look at using the propertychanged events of the BO and running your code from there.

Best of luck

Geoff.

For example, just create an _Loading private that is initially set to True.  Then in the OnLoad of the form, set this to False.  In the top of the SelectedIndexChanged, exit if this is set:

There are a number of other ways to get around this as well by just taking Nulls or possible invalid calls into account.  For example, if the BO is being called out of order, then use the InitializationPriority on the BO...y9ou may also want to change the population of one of the controls (if this depends on another) to manual instead of FormLoad, etc.

Thanks a lot.  This is an interesting approach on how to handle this situation and actually I ended up using the same concept for another case in a DropDown event and it worked just fine.

One more clarification for the combobox, which is the preferable event to handle in a validation case like this, the SelectedIndexChanged or SelectedValueChanged event?

I tried both with the _FormIsLoading approach and they both worked, but I like to be consistent with my coding and be clear as to which event to use for the same common validation.