Calling a control event by a string value?

[Rico]

Hello,

I have an issue that I'm actually dealing with in a VB6 app, but was
wondering if someone here happens to have an answer for this that I could
port to the VB6 app.

Is there a way to call an event from a string? I know I've seen code
that looks similar to the following;

Controls(control.name)("Validate") or
Controls(control.name).Events("Validate")

....at some point in my travels, but can't recall what the syntax was. The
reason I'm looking to do this is because the validate events on each field
are validating the data entered, setting the class properties and upon
leaving the form, are saving the values to the database through the
class.save method. The problem is when someone clicks on the "X" to close
the form down, the validate event does not fire. What I need to do is on
the UnloadQuery event of the form, cycle through the
controls and where the control does not equal the class property, run the
validate event. If the field is valid, then set the class property and
save, otherwise cancel the unloadquery event (similar to close or unload).

I know I've seen similar code and I'm sure it's not the last time it would
come in handy.

Any help would be appreciated.

Thanks!
Rick

 

[Jamie Collins]

I have an issue that I'm actually dealing with in a VB6 app, but was
wondering if someone here happens to have an answer for this that I could
port to the VB6 app.

Is there a way to call an event from a string? I know I've seen code
that looks similar to the following;

Controls(control.name)("Validate") or
Controls(control.name).Events("Validate")

...at some point in my travels, but can't recall what the syntax was. The
reason I'm looking to do this is because the validate events on each field
are validating the data entered, setting the class properties and upon
leaving the form, are saving the values to the database through the
class.save method. The problem is when someone clicks on the "X" to close
the form down, the validate event does not fire.

Within scope, you can call the event handler using its name and
supplying any parameters e.g.

Option Explicit
Private Sub Text1_Validate(Cancel As Boolean)
' Validation code here
End Sub
Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
Dim bCancel As Boolean
Text1_Validate bCancel
Cancel = bCancel
End Sub

An event handler is scoped as Private by default but there is nothing
(bar good software engineering principles <g>) preventing you from
changing it to Public.

Perhaps a better approach would be to have a separate Validate routine
that is called from all appropriate events e.g.

Option Explicit
Private Sub Text1_Validate(Cancel As Boolean)
Cancel = ValidateText1
End Sub
Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
Cancel = ValidateText1
End Sub
Private Function ValidateText1() As Boolean
' Validation code here
End Function

Obviously, such an approach does not scale well e.g. you need a
dedicated routine for each control (and remember to call them all) or
an all-singing-all-dancing routine which could be a maintenance
headache. How you solve the perceived problem depends on the amount of
significance of the validation routines, the potential for code reuse,
coder skill level, personal style, etc but there are lot's of
possibilities (VBA6 has a CallByName method if your personal style is
'quick and dirty' <g>).

Jamie.

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