The short answer to this is : don't use closeButton.PerformClick(). Do this instead:

((Sage.MMS.BaseForm)_form.UnderlyingControl).Close();

The long and boring answer is that the PerformClick() method (which is a method of the standard System.Windows.Forms.Form.Button) first calls an internal method, ValidateActiveControl, and will only continue and perform the Click action if that method returns true. Because the CustomerInvoiceLookup (which is made up of three PopupListTexteBoxes) won't have completed its validation by this point if you've entered text and tabbed/clicked off then this ValidateActiveControl will return false and the PerformClick method won't do anything.

Hi Chris, thank you. it works, I come across CloseIgnoringSave() and use it as well.

salesInvoiceForm = (Sage.MMS.BaseForm)_form.UnderlyingControl;
salesInvoiceForm.CloseIgnoringSave();

No - don't use CloseIgnoringSave(), there's a problem with it.  Whenever you open a form in Sage 200 an entry gets made in the SYSActiveLock table, and the entry is removed when the form is closed. This is to enable feature-level locking; for example, you won't be able to open the Sales Ledger Settings form if certain other forms are open.  CloseIgnoringSave doesn't remove the entry from SYSActiveLock and you'll end up with orphaned locks.

Instead, add a handler to form.DataAbandon, and in the handler set the IsDirty flag on the DataAbandonEventArgs to false. Then just call the form Close() method.

Hi Chris,

this is by DataAbandon handler

private void _form_DataAbandon(Sage.Common.UI.DataAbandonEventArgs e)
{
    e.IsDirty = false;
}

and in my CustomerSelected, I am using ((Sage.MMS.BaseForm)_form.UnderlyingControl).Close()

private void CustomerInvoiceLookup_CustomerSelected(object sender, EventArgs e)
        {
            CustomerInvoiceLookup cil = (CustomerInvoiceLookup)sender;
            try
            {
                if (Convert.ToInt32(cil.Customer.SLCustomerAccount) != 0)
                {
                    if (cil.Customer.CustomerAccount.ExchangeRateType == Sage.Accounting.EnumExchangeRateType.ExchangeRatePeriod
                    && cil.Customer.CustomerAccount.Currency.PeriodExchangeRatesToBase.First != null)
                    {
                        //validate if the exchange rate already expired and give warning to user
                        DialogResult ds = FXRateValidate.Business.BlockWarning.display(cil.Customer.CustomerAccount.Currency.PeriodExchangeRatesToBase, 
                            cil.Customer.CustomerAccount.Currency.Name);

                        if (ds == DialogResult.No)
                        {   //Close the current form
                            _form.Abandon(false);
                            ((Sage.MMS.BaseForm)_form.UnderlyingControl).Close()
                        }
                    }
                }
            }
            catch(Exception ex)
            {
                Logger.WriteLog("SalesInvoiceForm="+ex.ToString()+";");
            }
        }

but the earlier problem happen again. When using method 2 & 3 it did not close the form. Is my code correct?

Yeah, there *is* something weird going on with the CustomerInvoiceLookup control - it's to do with the event handlers of the three internal PopupListTextBoxes.  

Frankly, life is too short to try and make the control behave. If I were writing this then I'd go back to the CloseIgnoringSave but make sure the locks are disposed.  Like this:

private void CloseForm()
{
    var unLockBase = GetUnlockBaseMethod(_form.UnderlyingControl.GetType());
    unLockBase.Invoke(_form.UnderlyingControl, null);
    ((Sage.Accounting.Common.Forms.BaseForm)_form.UnderlyingControl).CloseIgnoringSave();
                       
}

private MethodInfo GetUnlockBaseMethod(Type fType)
{
    if (fType == typeof(object))
        return null;
    MethodInfo mi = fType.GetMethod("UnlockBase", 
    BindingFlags.Instance | BindingFlags.NonPublic);
    if (mi == null)
    {
        mi = GetUnlockBaseMethod(fType.BaseType);
    }
    return mi;
}

Then just call that custom CloseForm() method.

Thank you Chris, I will take this as the answer

A couple of extra points:

1. Rather than closing the form, it would be easier to follow the same pattern as Sage does for an account on hold: just clear the customerInvoiceLookup.  But I guess the spec says "Close the form"!

2. Don't forget that the form can be launched with the customer preselected (eg. from a workspace or desktop list) in which case the CustomerSelected event doesn't fire.

Good luck!

Hi Geoff, yes I got problem on point 2- I cannot catch the preselected customer on screen. Unable to monitor event as well to see which event are triggered. Any tips on how to catch it once customer is preselected?

Add a handler for the form Shown event (you'll have to cast form.UnderlyingObject), and in the handler do this:

private void MyTestForm_Shown(object sender, EventArgs e)
{
    if(customerInvoiceLookup.Customer != null && 
        !customerInvoiceLookup.Customer.PrimaryKey.IsNull)
    {
        //do stuff
    }
}

Thank you Chris. That works!