VB.Net/Development/Date Operation

Add a day, a month and a year to a Date

Imports System
Public Class MainClass
    Shared Sub Main()
        Dim dteStartDate As Date
        Dim dteChangedDate As Date
        "Start off in 2400
        dteStartDate = #2/28/2400#
        "Add a day and display the results
        dteChangedDate = dteStartDate.AddDays(1)
        System.Console.WriteLine(dteChangedDate.ToLongDateString)
        "Add some months and display the results
        dteChangedDate = dteStartDate.AddMonths(6)
        System.Console.WriteLine(dteChangedDate.ToLongDateString)
        "Subtract a year and display the results
        dteChangedDate = dteStartDate.AddYears(-1)
        System.Console.WriteLine(dteChangedDate.ToLongDateString)
    End Sub
End Class

Add time (days, hours) to current time

Imports System.IO
Module Module1
    Sub Main()
        Dim Dt As DateTime = Now()
        Dim NewDT As DateTime = Now()
        Console.WriteLine("Current date and time: " & Dt)
        NewDT = NewDT.AddHours(5)
        Console.WriteLine("Five hours from now is: " & NewDT)
    End Sub
End Module

Date Time and TimeSpan Demo

Imports System
Imports System.Diagnostics
Public Class MainClass
    Shared Sub Main()
        Const TRIALS As Integer = 10000000
        Dim start_time As DateTime
        Dim stop_time As DateTime
        Dim elapsed_time As TimeSpan
        Dim i As Integer
        start_time = Now
        For i = 1 To TRIALS
        Next i
        stop_time = Now
        elapsed_time = stop_time.Subtract(start_time)
        Console.WriteLine(elapsed_time.TotalSeconds.ToString("0.000000"))
        start_time = Now
        
        For i = 1 To TRIALS
             
        Next i
        stop_time = Now
        elapsed_time = stop_time.Subtract(start_time)
        Console.WriteLine(elapsed_time.TotalSeconds.ToString("0.000000"))   
    End Sub
End Class

Date Time Subtraction

Imports System
Public Class MainClass
    Shared Sub Main(ByVal args As String())
        Dim date1 As Date = #7/20/2004#
        Dim date2 As Date = #8/7/2004#
        Dim elapsed_time As TimeSpan
        elapsed_time = Date.op_Subtraction(date2, date1)
        Console.WriteLine(elapsed_time.Days.ToString)
          
    End Sub
End Class

Multiply Time Span

Imports System
Public Class MainClass
    Shared Sub Main(ByVal args As String())
        Dim ts1, ts2 As TimeSpan
        ts1 = New TimeSpan(1, 2, 3)
        ts2 = New TimeSpan(ts1.Ticks * 12)
        Console.WriteLine(ts1.ToString)
        Console.WriteLine(ts2.ToString)
          
    End Sub
End Class