Assigning Dates

Getting Started
1

Can someone please explain why I am observing this action.

Lets assume today is 30 May 2015

Dim myDate as New Date

my Date is 30 May 2015

Dim TestDate as Date = myDate

TestDate is 30 May 2015

TestDate.Day = 1

TestDate is 1 May 2015 BUT so is myDate. Why?
Doesn’t myDate copy to TestDate? It’s acting like a reference. How do I prevent myDate from changing on the assignment?
What am I missing?

Thanks

2

Think of Dates as a class. So you setting TestDate = Mydate makes them both the same object.

The documentation here:
http://documentation.xojo.com/index.php/Date.Constructor(CopyDate_as_Date)

Says you should do this:

dim testDate as New Date(MyDate)

Then they will be independent.

3

[quote=190837:@Michael Dosa]Can someone please explain why I am observing this action.

Lets assume today is 30 May 2015

Dim myDate as New Date

my Date is 30 May 2015

Dim TestDate as Date = myDate

TestDate is 30 May 2015

TestDate.Day = 1

TestDate is 1 May 2015 BUT so is myDate. Why?
Doesn’t myDate copy to TestDate? It’s acting like a reference. How do I prevent myDate from changing on the assignment?
What am I missing?

Thanks[/quote]
Try:

Dim TestDate As new Date TestDate.TotalSeconds = MyDate.TotalSeconds
Now you will have two separate dates.

Simon.

4

The copy constructor is better, imho.

5

Thanks Bob

dim testDate as New Date(MyDate) solves the issue.

md

6

Interesting. Where is that documented?

7

To make a proper copy, you’d have to copy the GMTOffset and then TotalSeconds. The constructor does that for you already (I think).

8

I was agreeing with you. What you posted is called a copy constructor.

9

Doh! Sorry. Kind of tired today.

10

All that partying in the mud.

11

Bob just wants to argue.

It’s red.

Right, red.

What?!? Prove it!

:slight_smile:

12

Not sure about the partying, but the standing all day, and walking through the mud, was exhausting.