However, changing the EventJavaScript in BeforeEventRender handler won't work (the one that you set last will be used).
You need to move this code to the client side:
<script type="text/javascript">
function clickHandler(e) {
if (e.value().substring(1,2) == 't') {
document.location = 'wfTdts.aspx?id=' + e.value();
}
else {
document.location = 'wfOpdts.aspx?id=' + e.value();
}
}
</script>
and
dpc.EventClickJavaScript = "clickHandler(e);";