onBeforeBlockSelect

event occurs before block selection

function onBeforeBlockSelect(
    // the id of start cell
    start: cellId,
    // the id of the end cell
    end: cellId,
    // is selection still in progress or finalized
    isFinal: boolean
): void

Example

dgrid.attachEvent("onBeforeBlockSelect", function(start, end, isFinal){
    return true;
});

Details

Return false to block selection

You can modify the start and end object to change the result of blockselection.