C#: Textbox1(Time) + Textbox2(Time) = Textbox3(Time)

Hi,

Hoping someone here can help me.

Im using c# windows application form and I have 3 textbox named startTimeTextBox, durationTextBox and endTimeTextBox.

startTimeTextBox and endTimeTextBox allowed input are in in format of TIME like HH:MM AM/PM (not in 24-hour format)

durationTextBox allowed input is in format of HH:MM  -means how many hours and minutes done for a specific work.

What I really want and need is the startTimeTextBox and durationTextBox will be computed for the endTimeTextBox. 

For example: startTimeTextBox = 09:00 AM and durationTextBox = 03:00, then endTimeTextBox = 12:00 PM, endTimeTextBox should be automatically populated after input for both startTimeTextBox and durationTextBox.

Hope I explained it well and hoping for the best solution ASAP. Thanks :)

Regards,

MukuroRokudo