Converting a float into a timespan

So, you're looking for... TimeSpan.FromHours(double)?

The documentation is your friend.

You want the FromHours method.

This takes a double (rather than a float) and returns a TimeSpan:

double hours = 1.5;
TimeSpan interval = TimeSpan.FromHours(hours);

To get the total hours from a TimeSpan use the TotalHours property:

TimeSpan interval = new TimeSpan(1, 15, 42, 45, 750);
double hours = interval.TotalHours;