C # Time Comparison

The previous period of time needs to be compared. compare (dt1, dt2), but to make it easier for me to obtain a string value, we have to compare it with the current time. For example, if I write 12:00:00, if convert. todatetime is followed by year, month, day, and all are zero !!. Later I thought that I only compared the time or datetime, so I changed my mind to compare the time.
Example: It is morning or afternoon.
Timespan minday = new timespan (12, 0, 0); // defines a noon time
Timespan time2 = timespan. Zero ;//
Timespan. tryparse (time, out time2); // time is the string time, which is converted to timespan
If (time2! = Timespan. Zero)
If (time2.compareto (minday) <0) // morning