General Methods of formatting and Subtracting DateTimes ASP.NET Style

We recently had a need to figure out how to subtract 7 days from a particular date and store it into a variable. What this turned into was an five day marathon of figuring out different ways of formatting dates using ASP.NET. This might seem a redundant but there are literals thousands of different ways of manipulating dates inside .NET. Here are my 17 ways I found along my adventure. Some people would say "find one way and just use it?". Not us, we decided to make this an adventure ...We recently had a need to figure out how to subtract 7 days from a particular date and store it into a variable. What this turned into was an five day marathon of figuring out different ways of formatting dates using ASP.NET. This might seem a redundant but there are literals thousands of different ways of manipulating dates inside .NET. Here are my 17 ways I found along my adventure. Some people would say "find one way and just use it?". Not us, we decided to make this an adventure and come up with a nice reference guide(for us anyway) if the occasion arises to format dates a certain way. We would suggest for anyone wanting to learn about .NET. Take about a week and just start out doing something with .NET and dig into documentation. If you find something new, learn about it and run with it for awhile. We did! [bold]Sample Code[/bold] Contained inside each method are various code samples. - Various Ways of Subtracting Time from a Current Date

'Uses the AddDays method to subtract X number of days
Public Function Date2()
Dim NewTime as DateTime
NewTime = DateTime.Now.AddDays(-7)
Dim s as string = NewTime
return s
End Function

'Thanks to Paul Czywczynski for this idea
'This probably (In My opinion) Offers the most flexibility found so far
'Change where the MM/dd/yyyy to whatever
'response.write(System.String.Format("{0:d}",NewTime))
'would return just the name of the Day
Function Date3()
Dim NewTime as DateTime = now.addDays(-7)
response.write(System.String.Format("{0:MM/dd/yyyy}",NewTime))
End Function


Function Date4()
Dim NewTime as DateTime
NewTime = now.addDays(-7)
return NewTime.ToString()
End Function



- General Formatting Techniques

'Uses the toLongTimeString method
Public Function Date5()
Dim NewTime as DateTime
NewTime = Now()
return newtime.toLongTimeString()
End Function

'Uses the toShortTimeString method
Public Function Date6()
Dim NewTime as DateTime
NewTime = Now()
return newtime.toShortTimeString()
End Function

'Uses the toLongDateString method
Public Function Date7()
Dim NewTime as DateTime
NewTime = Now()
return newtime.toLongDateString()
End Function

'Uses the toShortDateString method
Public Function Date8()
Dim NewTime as DateTime
NewTime = Now()
return newtime.toShortDatestring()
End Function



- Using FormatDateTime Function

'Uses FormatDateTime function General format
Function Date9()
Dim NewTime as DateTime
NewTime = DateTime.Now.Subtract( New TimeSpan(7, 0, 0, 0) )
return formatdatetime(NewTime, 0)
End Function

'Uses FormatDateTime function LongDate format
Function Date10()
Dim NewTime as DateTime
NewTime = DateTime.Now.Subtract( New TimeSpan(7, 0, 0, 0) )
return formatdatetime(NewTime, 1)
End Function

'Uses FormatDateTime function ShortDate format
Function Date11()
Dim NewTime as DateTime
NewTime = DateTime.Now.Subtract( New TimeSpan(7, 0, 0, 0) )
return formatdatetime(NewTime, 2)
End Function

'Uses FormatDateTime function LongTime format
Function Date12()
Dim NewTime as DateTime
NewTime = DateTime.Now.Subtract( New TimeSpan(7, 0, 0, 0) )
return formatdatetime(NewTime, 3)
End Function

'Uses FormatDateTime function ShortTime format
Function Date13()
Dim NewTime as DateTime
NewTime = DateTime.Now.Subtract( New TimeSpan(7, 0, 0, 0) )
return formatdatetime(NewTime, 4)
End Function



- Display Specific parts of the Date(DAY, MONTH, TIME)

'Bring Back just the name of the Day
Function Date14()
Dim NewTime as DateTime = now.addDays(-7)
dim s as string
s = (System.String.Format("{0:dddd}",NewTime))
Return s
End Function

'Returns the Integer of what day of week
Function Date15()
Dim MyDate as DateTime
Dim MyWeekDay as Integer
MyDate = Now.AddDays(-5)
MyWeekDay = Weekday(MyDate)
return MyWeekDay
End Function

'Returns the Month Integer
Function Date16()
Dim MyDate as DateTime
Dim MyMonth as Integer
MyDate = Now.AddDays(-5)
MyMonth = Month(MyDate)
return MyMonth
End Function

'Returns just a formatted string
'This method provides just formatting but
'Very flexible with not a lot of code
Function Date17()
Dim MyDate as String
MyDate = Format(Now(), "yyyy")
return MyDate
End Function
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[bold]Formatting Dates Reference Guide[/bold]
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[bold]d[/bold] Short Date [bold]D[/bold] Long Date [bold]f[/bold] Full (long date + short time) [bold]F[/bold] Full (long date + long time) [bold]g[/bold] General (short date + short time) [bold]G[/bold] General (short date + long time) [bold]m, M[/bold] Month/Day Date [bold]r, R[/bold] RFC Standard [bold]s[/bold] Sortable without TimeZone info [bold]t[/bold] Short Time [bold]T[/bold] Long Time [bold]u[/bold] Universal with sort able format [bold]U[/bold] Universal with Full (long date + long time) format [bold]y, Y[/bold] Year/Month Date [bold]*Note:[bold] Some systems will not be able to get dates for 2-digit years of less than 1930.
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