How to iterate checked checkedbox data in kendo gird?

I am a new programmer and I have some problems:

1. I have a grid with checkbox column. Let say there are 10 rows of data and I checked 5 of them. How to loop 5 of them to get those datas?

2. On the header of checkbox column, there is a single checkbox (check All). If I checked it, all the checkbox bellow is automatically checked. I already handle that, the question is how to enable/disable it? The condition is: if the name column contain the same name, "check all" is enable. If the name column is contain different name, it will be disable.