Using a Codeptr instead of Function name when adding DDT control?

[Mike Joseph]

Hi. I'm wondering if its possible to use a Codeptr instead of a function name when adding a DDT control?

e.g.

Callback Function Test() as long
     Msgbox "hi"
End FUnction

Sub TryIt()
     lFunc = CODEPTR(Test)
     CONTROL ADD BUTTON, hWin, %CTL_ID, "Caption", _
     x,y,xx,yy, 0, CALL lFunc
End Sub

When I run the above, i get an error "undefined label/line reference" Any ideas? The reason I need to do this is because my controls need to be created dynamically from a script and the specific call back function to be used for a particular button is also specified in the script.

-Mike

[This message has been edited by Mike Joseph (edited June 27, 2000).]

[jcfuller]

Mike,
The way I would handle it is to use a common callback function for
all your controls and from there use CALL DWORD with the CODEPTR of the
function you want.

James


------------------

[Eric Pearson]

Mike --

The CONTROL ADD function does not support CALL DWORD, in part (I would speculate) because you must use a special CALLBACK function, not just any old function. And since the compiler has no way of knowing whether or not your lFunc points to a CALLBACK function or a regular function...

Your best bet is probably to simulate the effect you're looking for, by using an IF/THEN block inside your CALLBACK FUNCTION. This is only pseudo-code, but I'm picturing something like this:

Callback Function MasterCallback() as long
  
    DIM dwFunc1 AS GLOBAL DWORD
 
    IF CBCTL = %CTL_ID THEN
    	CALL DWORD dwFunc1 USING (...) CBHNDL, CBCTL, CBWPARAM, CBLPARAM
    ELSEIF CBCTL = %etc.
        CALL DWORD etc.
    ELSEIF...
        etc.
    END IF
 
End Function
 
Sub TryIt()
    DIM dwFunc1 AS GLOBAL DWORD
    dwFunc1 = CODEPTR(Test)
    CONTROL ADD BUTTON, hWin, %CTL_ID, "Caption", _
                        x,y,xx,yy, 0, CALL MasterCallback
End Sub

If you want to keep things organized, instead of using separate variables like dwFunc1 I'd suggest using a two-dimensional DWORD array, where the first column stores the %CTL_ numbers and the second column stores the CODEPTR values. Better yet, use a single-dimension DWORD array to store the CODEPTR values, and use %CTL_ID = 1, etc. so that the control numbers themselves tell you which array element to use...

Callback Function MasterCallback() as long
  
    DIM dwFunc() AS GLOBAL DWORD
 
    CALL DWORD dwFunc(CBCTL) USING(...) CBHNDL,CBCTL,CBWPARAM,CBLPARAM TO lResult

    FUNCTION = lResult
 
End Function

-- Eric


------------------
Perfect Sync: Perfect Sync Development Tools
Email: mailto:[email protected][email protected]</A>



[This message has been edited by Eric Pearson (edited June 27, 2000).]

[Mike Joseph]

Thanks guys.

------------------

[jcfuller]

Mike,
I forgot to mention that I have code so you can roll your own Dialogs at
run time. I use it with a script engine I created. If you're interested email
me at mailto:[email protected][email protected]</A>

James


------------------




[This message has been edited by jcfuller (edited June 29, 2000).]