Forum Discussion

MulgraveTester's avatar
MulgraveTester
Frequent Contributor
9 years ago

How can I use scroll bar methods

I have a script that uses [PageDown] to move from the top of a SysListView32 to the bottom. Unfortunately the [PageDown] key causes unwanted behaviour so I want to use the vertical scroll bar instead...
  • djadhav's avatar
    djadhav
    9 years ago

    What I usually do is this

     

    'Prepare to know when to stop scrolling
'Identify an object on the top of the page/list to know that you've scrolled completely to the top
	SET objTop = objParent.FindChild(PropArray, ValuesArray, depth)
'Identify an object on the botton of the page/list to know that you've scrolled completely to the top
	SET objBottom = objParent.FindChild(PropArray, ValuesArray, depth)

'Scroll to the required object	
'Find the object that we are interested in 	
	SET objChild = objParent.FindChild(PropArray, ValuesArray, depth)
	IF objChild.VisibleOnScreen THEN
		'Do something with the object
	ELSE
		DO WHILE NOT objTop.VisibleOnScreen
			lib_MouseScrollUp(objPage,5) 'Find a number that sufficiently scrolls for you and use scroll up or down methods as required
			IF objChild.VisibleOnScreen THEN EXIT DO 
		LOOP
END IF

'Functions for scrolling

FUNCTION lib_MouseScrollUp(ByRef obj, ByVal count)
  obj.MouseWheel count
END FUNCTION

'OR

FUNCTION lib_MouseScrollDown(ByRef obj, ByVal count)  
  obj.MouseWheel 0-count
END FUNCTION

     

MulgraveTester's avatar
MulgraveTester
Frequent Contributor

The ListView32 does not have a .Window("TScrollBar") object, so none of the help seems relevant.

 

There are 300 items in my list object with 42 in view at any one time.

I've found that the vScroll.Pos property is read/write so I can set the position with

   myObj.vscroll.Pos = 41

 

This works for some values but I get an error for others

"Failed to set position 41 for the scroll bar. 42 was set instead."

 

There is nothing in the application that prevents me sliding the scrollbar to any position with the mouse, so now I am wondering why some values are Ok and some are not. How do I slide the scrollbar without creating errors?

Colin_McCrae's avatar
Colin_McCrae
Community Hero
9 years ago

41 probably fails if the object is not visible at that pont.

 

(You mention there are only 42 of 300 visible)

 

So I suspect it doesn't work if you try and point it to a non-visible item and it goes to the next available visible one.

  • Colin_McCrae's avatar
    Colin_McCrae
    Community Hero
    9 years ago

    Or do you mean 42 of the 300 are visible within the scrollable window?

     

    Does the containing window not have any other scroll methods?

    • MulgraveTester's avatar
      MulgraveTester
      Frequent Contributor
      9 years ago

      Hi Colin,

      The list shows item 0 to 41. There are 300 items in total.

      I should be able to select any index in the range 0 to 259 (300 - 41). Some values are fine but others generate the error.

       

      I think the list is a CodeJock control, which is why the scroll bar is not standard. It has a VScroll element that has Max, Min and Pos properties. By setting the Pos I get this error. I get the error even without using any code because I can edit the Pos property in the object spy. (See attached)

      • sergeys's avatar
        sergeys
        Contributor
        9 years ago

        Could you please provide screenshot with methods that are available for that control, and filter them by 'scroll'.

        I've been using only ScrollIntoView method that takes object to scroll to as parameter, but it depends on how your contol is implemented.