In v1.3 we have implemented the ability to handle MultiRow selections.
As stated in the roadmap.
"Added the ability for a grid section to have "Multi Select Rows". This displays a checkbox column for each row. As the user clicks a checkbox, the "selectionChanged" delegate is called with a comma separated list of values. These values are determined by the "Multi Select Row Expression" e.g. You can multi select rows in a grid and then call your own business procedure to handle app specific business logic."
This is how it looks at runtime.

And these are the attributes you need to set for the grid section to enable this functionality.

The "selectionChanged" delegate itself looks like this.
Code:
////////////////////////////////////////////////////////////////
// Event delegate for 'selectionchanged' event
proc page1_section2_selectionchanged(arg)
// 'arg' is a comma separated list of items selected
// It can be used directly to load the selected items into a ListBox
Lianja.writeOutput("selectionChanged() arg="+arg)
endproc
Enjoy.
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