How to use " if " condition for multiple checkbox in asp.net?

I used 30 Checkboxes in a table,5 rows and 6 columns.5 Checkbox in each row. I need to satisfy two conditions within this table.

1.The first condition is when three Checkboxes are selected continuously it should display ("You can't select continuous hours"). 2.Next condition is,it shouldn't select more than three checkbox in each row.