Hi,
there is an alternative way you might want to take a look at. You simply change the value of the property "checked" in your JSON model and update the bindings. Here is how the changed coding for the last part of the event handler of the button:
for(var i = 0; i < data.length; i++){ data[i].checked = isChecked; }; oModel.updateBindings();
The model "DataContModel" and the coding to determine the Row Count can be skipped here.
Regards, Frank