`DateTime.Now`

With this property we get a copy of a Structure that stores the current time. We demonstrate DateTime.Now and show how it changes when accessed at a later time.

Now changes when called the same way at different points in time. It has no side effects. For optimization, consider caching the result of DateTime.Now.

An example

When we assign to DateTime.Now, the current time is copied to a storage location. This means that the time stored will never change after that point.

Step 1 When you access DateTime.Now, the current time is computed. This is stored in a Structure.

Step 2 The Sleep call causes 10 seconds to pass. So the current time has changed.

Step 3 The second DateTime returned by Now is 10 seconds later. The value returned by Now keeps changing.

Module Module1
    Sub Main()

        ' Step 1: load now into local variable.
        Dim now As DateTime = DateTime.Now
        Console.WriteLine(now)

        ' Step 2: sleep 10 seconds.
        Threading.Thread.Sleep(10000)

        ' Step 3: use property again.
        Console.WriteLine(DateTime.Now)

    End Sub
End Module6/23/2022 6:35:07 AM
6/23/2022 6:35:18 AM

Today

Here we compare the result of DateTime.Now with DateTime.Today. The Today property is the same as Now, but with the time stripped.

So We can use Today instead of Now when we do not want the time part of the DateTime structure.

Module Module1
    Sub Main()

        Console.WriteLine("NOW:   {0}", DateTime.Now)
        Console.WriteLine("TODAY: {0}", DateTime.Today)

    End Sub
End ModuleNOW:   2/3/2020 4:33:38 AM
TODAY: 2/3/2020 12:00:00 AM

DateTime.Now can be stored in a local variable. The value of "Now" changes with time. Conceptually DateTime.Now acts as a method that returns the current time.