Calculate date using datetimepicker

Question

Hi,

 

I have created

 

* 1 Datetimepicker (from date)

* 1 Comboxbox (How many days)

* 1 Textbox (Here it should display . Fromdate + How many days u select)

 

In the Combobox u select the from date in the combobox i have days 5,10,15,30 .

In the textbox i want to display the date.

 

So an example if i select 2014-02-22 in the DateTimePicker and in the Combox 5 Days i want it to display 2014-02-25 in the textbox.

 

Any Suggestions?