Question

I have to 2 dropdownlists and I want to populate them with their values as hours from 1 to 24. Then I want to calculate the difference between the two selected values. If i choose in the first dropdown let’s say the hour value as 12 AND second value as 16 then the difference will be 4.

How can I achieve that in c#?

I’m developing a asp.net web application coded in C#.

Below is the code of how I populate my dropdownlist:

 DateTime Date = DateTime.Today;
 DateTime Time = DateTime.Now;
 ListItem item1 = new ListItem(Time.ToShortTimeString(),
                               Time.ToShortTimeString());
         
 for (int i = 0; i <= 48; i++)
 {
   ListItem item2 = new ListItem(Date.ToShortTimeString(), 
                                 Date.ToShortTimeString());
             
   droplist.Items.Add(item2);
                
               
   if (Date.CompareTo(Time) < 0 && Date.AddMinutes(30).CompareTo(Time) > 0)
     droplist.Items.Add(item1);
                    
   Date = Date.AddMinutes(60);
 }

How can I assign values to my dropdown, values being the hours?

Answer 1

Instead of adding the date/time string to the drop down, you may add the DateTime value itself. The dropdown displays its members by calling ToString(). The disadvantage here: you are not able to use another time format like ToShortTimeString().

Another way is to use the DateTime.TryParse method to convert back before calculating.