Use cdlOFNOverwritePrompt as condition? 1

[Svanholm]

Is it possible to use cdlOFNOverwritePrompt as condition?

To be specific: I wish to let my program act in one way if cdlOFNOverwritePrompt dialog box appears during runtime and another way if it does not.

A simple coding example:

With CommonDialog1
   .Flags = cdlOFNOverwritePrompt 
   .ShowSave
End With

If cdlOFNOverWritePrompt Then 'Here is where it does not work
MsgBox Prompt:=("OverwritePrompt Dialog Box appeared")
End If

MsgBox Prompt:=("OverWritePrompt Dialog Box did not appear")

Problem is that the coding activates the if-statement whether or not the cdlOFNOverwritePrompt dialog box appears.

Is there a way around it?

What I am trying to do with this is to make one thing happen if the current file already exists and another if it does not.

 

[BobRodes]

Thanks Hugh, of course that's so. However, if speed is the consideration, doesn't "if a$ <> 0" avoid a cast to boolean that "if a$" requires, and therefore isn't it more efficient?

<They are both equally right.
Well, even if they aren't equally "right", any difference they may have is unlikely to be a practical one. My other answer to strongm's question is "because he thinks it's prettier," which is of course a valid reason to adopt one syntax over another when the differences in efficiency are purely academic.

Bob

 

[HughLerwill]

>However...

Copy this into a Form; you'll need a Command1 and a Command2

Private Sub Command1_Click()

Dim i&
Dim t!
t = Timer
For i = 1 To 100000000
If Len(a$) Then

End If
Next
Print Timer - t

End Sub

Private Sub Command2_Click()

Dim i&
Dim t!
t = Timer
For i = 1 To 100000000
If a$ = "" Then

End If
Next
Print Timer - t

End Sub

Notwithstanding precision timers I figure it's nearly twice as quick and just use it.

 

[Svanholm]

Hmmm?

On my pc, they both take almost exactly 10 sec to calculate.

What is being timed? counting to a billion or what?

 

[HughLerwill]

>What is being timed?

One loop is using If Len(a$), the other uses If a$ = "".

In the IDE I get about 2 seconds and 4 seconds respectively. Compiled about .4 seconds and 2 seconds.

 

[BobRodes]

Interestingly, when I used your code, Hugh, and then added another button to evaluate len(a$) = 0 I was surprised to find that the boolean cast was a bit faster than the integer evaluation. So I tried this:

Option Explicit

Dim a$

Private Sub Command1_Click()

    Dim i&
    Dim t!
    t = Timer
    For i = 1 To 100000000
        If Len(a$) Then
        
        End If
    Next
    Debug.Print Timer - t

End Sub

Private Sub Command2_Click()
    
    Dim i&
    Dim t!
    t = Timer
    For i = 1 To 100000000
        If a$ = "" Then
        
        End If
    Next
    Debug.Print Timer - t

End Sub

Private Sub Command3_Click()
    
    Dim i&
    Dim t!
    t = Timer
    For i = 1 To 100000000
        If Len(a$) = 0 Then
        
        End If
    Next
    Debug.Print Timer - t

End Sub


Private Sub Form_Load()
a$ = "Hello world"
End Sub

I found that Command1 averaged about 3.5 seconds, Command2 about 5.5 seconds, and Command3 about 3 seconds.

Bob

 

[HughLerwill]

Bob, Your use of Debug.Print tells me you have not tried it compiled, in this case it makes quite a difference. It's compiled that counts...

Compiled with straight Print (to Form) and ramping it up to 100,000,000 (another 10x) loops I get;

Command1 3.06 100% ref
Command2 18.30 590% this is significant
Command3 3.03 99% I take note it's better but we are spitting hairs now

When we and the computers were young stuff like this made a real difference; nowdays it is'nt so critical but take a few such techniques, use them routinely, and the exe will still be faster and smaller.

 

[BobRodes]

Good point, Hugh, and of course I should have done that. Anyway, yes, we are splitting hairs, and we always have been. As I mentioned before, any difference is unlikely to be a practical one. Furthermore, on my machine, they ran at the same speed exactly once I compiled them.