If you are trying it out with ASP.Net and C# then below solution can help you out to start.
[
Asp.Net Calendar control with Time]
If you need a control in Win form and c# then below is an example you can look out.
C# DateTimePicker Control[
^]
For the Win form example you need to add three drop downs as you can see it was done in Asp.net solution and proceed with your solution.
N.B: Please don't copy paste the samples provided .Go through the examples try to see how they are achieving their need and then you atry to implement yours with certain changes required.
Tha above solution provided are also looks good for me:)