PRB: Setting a Filter Allows no Real Time Scrolling in Listbox

• Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a, 6.0

SYMPTOMS

When using the scroll button of a combo or list box to scroll through data that has a SET FILTER TO expression, the data in the combo or list box will not be refreshed to show the new data until the mouse button is released. If there is no SET FILTER used on the data the data moves as the scroll button moves and immediately displays the new data.

NOTE: Setting DELETED ON in Visual FoxPro 6.0 causes the same behavior to occur.

STATUS

This behavior is by design. When any type of filter is used there is no real time scrolling of data in a combo or list box.

MORE INFORMATION

Steps to Reproduce Behavior

1. Copy the following code into a program (.prg) file and then run the program. This code uses the customer.dbf sample table that comes with Visual FoxPro. Make sure that a path is set to the table:




   PUBLIC oform
        oform = CREATEOBJECT("frmFilterTest")
        oform.Show
    
        DEFINE CLASS frmFilterTest AS form
              Top = 0
              Left = 0
              Height = 255
              Width = 354
              DoCreate = .T.
              Caption = "frmFilterTest"
              Name = "frmFilterTest"

              ADD OBJECT cboFilter AS combobox WITH ;
                        RowSourceType = 6, ;
                        RowSource = "customer.cust_id", ;
                        Height = 24, ;
                        Left = 24, ;
                        Top = 36, ;
                        Width = 100, ;
                        Name = "cboFilter"

              ADD OBJECT lstCustomer AS listbox WITH ;
                        RowSourceType = 6, ;
                        RowSource = "customer.cust_id", ;
                        Height = 170, ;
                        Left = 180, ;
                        Top = 24, ;
                        Width = 100, ;
                        Name = "lstCustomer"

              ADD OBJECT cmdFilter AS commandbutton WITH ;
                        Top = 156, ;
                        Left = 24, ;
                        Height = 27, ;
                        Width = 84, ;
                        Caption = "Filter On", ;
                        Name = "cmdFilter"

              PROCEDURE Load
                        SET DELETED OFF
                        SET FILTER to maxordamt > 1000

              PROCEDURE cmdFilter.Click
                        IF This.caption='Filter On'
                                SET FILTER TO
                                This.caption='Filter Off'
                        ELSE
                                SET FILTER TO maxordamt > 1000
                                This.caption='Filter On'
                        ENDIF 

2. Move the scroll button of the list or combo box and note that the data does not refresh until the mouse button is released.



3. Select the Set Filter command button to turn the filter off and note that the data moves interactively when the scroll button is moved.



4. Changing the SET DELETED OFF command to ON in the Load event of the code causes the same behavior to occur in both the combo and list boxes when you use Visual FoxPro 6.0.

Additional query words: KBDSE

Keywords : kbContainer kbCtrl kbVFp500 kbVFp500a kbVFp600 kbGrpFox kbDSupport kbCodeSnippet
Version : WINDOWS:5.0,5.0a,6.0
Platform : WINDOWS
Issue type : kbprb