Low Level Direct Access To The Visualization List in VLF-ONE Instance Lists

In VLF-ONE code you can directly access the Visual LANSA list (class #PRIM_LIST) that is used to visualize the instance list content.

Filter and command handler code can access the list control in instance list handlers, using method avListManager.avVisualList. This returns a reference to the PRIM_LIST object, if it is available.

Once you have a reference to the list you can access its items and columns, using the standard VL collection properties.

Direct access is only available if:

• the instance list handler implements the list as a PRIM_LIST

• the instance list handler makes the list available. (The standard instance list handlers VF_UM040O and VF_UM044O do)

This allows filters to make minor changes to the appearance of the instance list.

For example if the instance list normally looks like this:

You could modify it from the filter, so that it looks like this:

Using code in the filter's uInitialize routine that looks like this:

Some Significant Usage Points

Some Examples