Find highest date

This was fun...

For this sample to work J, add 2 Listboxes to your form, and 1 button.

Declare this at the top of "Windows Form Designer generated code" :
Private dates() As Date

Add this to Button1_Click() :
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

ReDim dates(9)
Dim rdDates As New Random 'Declare new random object

For i As Integer = 0 To 9
Dim d As Date = (Date.Today.AddDays(-rdDates.Next(0, 10000)))
ListBox1.Items.Add(d.ToString()) 'add to listbox
dates(i) = d
Next
' new instance of the custom sorter.
Dim sorter As New DateSorter 'see next code block
' sort with the custom sorter
Array.Sort(dates, sorter)

For i As Integer = 9 To 0 Step -1 'loop backwards, because highest date is last element
ListBox2.Items.Add(dates(i))
Next

MessageBox.Show("Highest Date = " & dates(9).ToString())
MessageBox.Show("Lowest Date = " & dates(0).ToString())
End Sub

This will add random dates into the first listbox - just so that we have a few dates to work with - you must add your own dates you want to test to an aary as well. Then the dates will get sorted and displayed from highest to lowest in the listbox2.
It will also show 2 messageboxes - one for the highest date, one for the lowest. :rolleyes: :)

This sorting, is actually done in the following class (which you can add to the bottom of your form's class). This class uses the IComparer Interface, which IMHO, is the best way to compare lists.. :
Public Class DateSorter
Implements IComparer

Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare
' we have to test x against y and return :
'<0 if x is less than y.
'0 if x equals y.
'>0 if x is greater than y.
' see msdn Icomparer.compare
Dim datex As Date = DirectCast(x, Date)
Dim datey As Date = DirectCast(y, Date)
' date.compare(t1, t2)
'Value Type Condition
'Less than zero t1 is less than t2.
'Zero t1 equals t2.
'Greater than zero t1 is greater than t2.
'
'so just:
Return Date.Compare(datex, datey)
End Function
End Class

I am attaching the VB 2003 sample with ;)

I hope it helps :D

so basicly in my function i have now done this

[code]
''''
Dim sorter As New DateSorter
'sort with the custom sorter
DaArr.Sort(sorter)
DOLP = DaArr.Item(0)
Return DOLP
End Function
[code]

where DaArr is an arraylist not an array
Lets see if it works

hey, there is one of these things uh what are they called again uh
problematic things uh
exceptions

it said invalid cast, so i changed directcast to ctype
now no more exception and it works, but it selectd the lowest date.
should i maybe set my variable = to the last in the array instead of the first?

hey, there is one of these things uh what are they called again uh
problematic things uh
exceptions:eek:
Mine was fine :) Does yours work now
should i maybe set my variable = to the last in the array instead of the first?
Yes :)

That's good, J! Well done! :thumb:

Glad that I was able to help :)

jeez, now that seems quite a bit easier than 2003, but i dont have 2005, yet, when i get it ill be sure to use that way instead.
6 lines wow.

i wish the function i was bz with now was that short, up to 300 lines and it calls other functions(lots of them). getting a bit messy now :-)

Thanks ANI
J