SetCtrlIndex Causes Library Errors

[hornsbyr]

LabWindows CVI 9.0.1 (375)

Windows XP Pro

I am getting Library Function Error (return value == -55(0xffffffc9) The index passed is out range.

The code snippet is:

/**START**/

GetNumListItems(panelHandle,PANEL_LISTBOX,&ListCount);

if(0 != ListCount)

    SetCtrlIndex(panelHandle,PANEL_LISTBOX,(ListCount-1));

/**END**/

The error occurrs in the SetCtrlIndex function.

Also, I see the same error in similar code:

/**START**/

GetNumListItems(panelHandle,PANEL_LISTBOX,&TotalCount);

GetLabelFromIndex(panelHandle,PANEL_LISTBOX,(TotalCount - 1), LabelBuff);

/**END**/

The error occurrs in the GetLabelFromIndex function. 

The number of list items is greater than zero in both cases.

Any Ideas?

Rodney

[DianaS]

Hi Rodney

I tried to reproduce this here.

But it works.

Attached you get the project.

[DianaS]

Hi Rodney

I tried to reproduce this here.

But it works.

Attached you get the project.

[hornsbyr]

My project uses a llistbox as a text box to write status information to a user. The updates to the listbox occur randomly. I have a callback function attached to an async timer at 0.2 second to do this:

/**START**/

GetNumListItems(panelHandle,PANEL_LISTBOX,&ListCount);

if(0 != ListCount)

    SetCtrlIndex(panelHandle,PANEL_LISTBOX,(ListCount-1));

/**END**/

It does not happen all the time but it happens enough to cause potential problems. Every time the debugger breaks on the library error, I inspect the value of ListCount. The value is always greater than zero. So, when I subtract one, I should have a valid index into the listbox but I still get the Library Function Error (return value == -55(0xffffffc9) The index passed is out range.

Rodney

[DianaS]

Can you attach your project to see this behavior here?