Binarysearch in Arraylist can this be done?

[Mike Dole]

I have an arraylist like the one with the Guitar Class sample in
Q316302.

Dim MycolliCol as arraylist
Private Sub FillArray()
MyColliCol.Add(New Colli(1, "STUK", 0))
MyColliCol.Add(New Colli(16, "ROL", 1))
MyColliCol.Add(New Colli(17, "BOS", 2))
MyColliCol.Add(New Colli(18, "DOOS", 0))
MyColliCol.Add(New Colli(19, "PAK", 0))
MyColliCol.Add(New Colli(20, "PANEEL", 0))
MyColliCol.Add(New Colli(21, "PALLET", 0))
MyColliCol.Add(New Colli(22, "BAK", 0))
MyColliCol.Add(New Colli(23, "PRES", 0))
MyColliCol.Add(New Colli(24, "DEUR", 0))
MyColliCol.Add(New Colli(25, "KAP/RAIL", 0))
End Sub
'I've placed the search in the form1_load for testing...

Private Sub Form1_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles MyBase.Load
FillArray()

Dim myObjectOdd As Object = New Colli(1, "STUK", 0)
FindMyObject(MyColliCol, myObjectOdd)

End Sub

Public Shared Sub FindMyObject(ByVal myList As ArrayList, ByVal
myObject As Object)
Dim myComparer As System.Collections.IComparer
Dim myIndex As Integer = myList.BinarySearch(1, 11, MyObject,
myComparer)
If myIndex < 0 Then
Console.WriteLine("The object to search for ({0}) is not
found. " _
+ "The next larger object is at index {1}.", myObject,
_
Not myIndex)
Else
Console.WriteLine("The object to search for ({0}) is at
index " _
+ "{1}.", myObject, myIndex)
End If
End Sub

Gives me an argument exception (guess because 'value' is not of the
same type as the elements of the ArrayList).

But neither does it work if I use:

FindMyObject(MyColliCol, "STUK")

I just want to be able to search through the arraylist (or a
collection) and use it as a converter between the integers and the
string. For instance when I search for 24 I want "DEUR" to be
returned..

If there is (hopefully an easier) way to do things like this, please
let me know.

I must admit this is getting way above my head...

Thanks in advance,

Mike

[Russell Jones]

This may be closer to what you're looking for. The following example adds
integer values (keys) and strings (values) to a Hashtable, which is a
collection type that accepts objects for both keys and values. If you know
the key, you can retrieve the value.

Dim ht As New Hashtable
ht.Add(1, "One")
ht.Add(2, "Two")
ht.Add(3, "Three")
ht.Add(4, "Four")
ht.Add(5, "Five")
ht.Add(6, "Six")
ht.Add(7, "Seven")
ht.Add(8, "Eight")
ht.Add(9, "Nine")
ht.Add(10, "Ten")

Dim searchText As String = Me.TextBox1.Text ' TextBox1 is a textbox on
a form that contains the lookup value (a string from "1" to "10" in this
case
Try
' Get the integer value of the number entered by the user
Dim searchInt As Integer = Integer.Parse(searchText)

' find the matching string value, if available
Dim foundText As String = CType(ht.Item(searchInt), String)
If foundText Is Nothing Then
Console.WriteLine("Couldn't find a text value for the number
{0}.", searchInt)
Else
Console.WriteLine("The text value of {0} is {1}.", searchInt,
foundText)
End If
Catch ex As Exception
' if user enters anything but a valid integer, this error occurs.
Console.WriteLine("Invalid number. Enter an integer number.")
End Try

Note that you have to cast values back to the correct types to use them. In
your case, the code would look more like:
ht.Add (1, New Colli(1, "STUK", 0))
ht.Add(16, New Colli(16, "ROL", 1))

And when you retrieve an item by its integer key, you'll need to cast the
object back to Colli, and extract the 2nd field value of that Colli object
to get the name.
"Mike Dole" <m_******@hotmail.com> wrote in message
news:fd**************************@posting.google.c om...

I have an arraylist like the one with the Guitar Class sample in
Q316302.

Dim MycolliCol as arraylist
Private Sub FillArray()
MyColliCol.Add(New Colli(1, "STUK", 0))
MyColliCol.Add(New Colli(16, "ROL", 1))
MyColliCol.Add(New Colli(17, "BOS", 2))
MyColliCol.Add(New Colli(18, "DOOS", 0))
MyColliCol.Add(New Colli(19, "PAK", 0))
MyColliCol.Add(New Colli(20, "PANEEL", 0))
MyColliCol.Add(New Colli(21, "PALLET", 0))
MyColliCol.Add(New Colli(22, "BAK", 0))
MyColliCol.Add(New Colli(23, "PRES", 0))
MyColliCol.Add(New Colli(24, "DEUR", 0))
MyColliCol.Add(New Colli(25, "KAP/RAIL", 0))
End Sub
'I've placed the search in the form1_load for testing...

Private Sub Form1_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles MyBase.Load
FillArray()

Dim myObjectOdd As Object = New Colli(1, "STUK", 0)
FindMyObject(MyColliCol, myObjectOdd)

End Sub

Public Shared Sub FindMyObject(ByVal myList As ArrayList, ByVal
myObject As Object)
Dim myComparer As System.Collections.IComparer
Dim myIndex As Integer = myList.BinarySearch(1, 11, MyObject,
myComparer)
If myIndex < 0 Then
Console.WriteLine("The object to search for ({0}) is not
found. " _
+ "The next larger object is at index {1}.", myObject,
_
Not myIndex)
Else
Console.WriteLine("The object to search for ({0}) is at
index " _
+ "{1}.", myObject, myIndex)
End If
End Sub

Gives me an argument exception (guess because 'value' is not of the
same type as the elements of the ArrayList).

But neither does it work if I use:

FindMyObject(MyColliCol, "STUK")

I just want to be able to search through the arraylist (or a
collection) and use it as a converter between the integers and the
string. For instance when I search for 24 I want "DEUR" to be
returned..

If there is (hopefully an easier) way to do things like this, please
let me know.

I must admit this is getting way above my head...

Thanks in advance,

Mike

[Tom Shelton]

In article <fd**************************@posting.google.com >, Mike Dole wrote:

I have an arraylist like the one with the Guitar Class sample in
Q316302.

Dim MycolliCol as arraylist
Private Sub FillArray()
MyColliCol.Add(New Colli(1, "STUK", 0))
MyColliCol.Add(New Colli(16, "ROL", 1))
MyColliCol.Add(New Colli(17, "BOS", 2))
MyColliCol.Add(New Colli(18, "DOOS", 0))
MyColliCol.Add(New Colli(19, "PAK", 0))
MyColliCol.Add(New Colli(20, "PANEEL", 0))
MyColliCol.Add(New Colli(21, "PALLET", 0))
MyColliCol.Add(New Colli(22, "BAK", 0))
MyColliCol.Add(New Colli(23, "PRES", 0))
MyColliCol.Add(New Colli(24, "DEUR", 0))
MyColliCol.Add(New Colli(25, "KAP/RAIL", 0))
End Sub
'I've placed the search in the form1_load for testing...

Private Sub Form1_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles MyBase.Load
FillArray()

Dim myObjectOdd As Object = New Colli(1, "STUK", 0)
FindMyObject(MyColliCol, myObjectOdd)

End Sub

Public Shared Sub FindMyObject(ByVal myList As ArrayList, ByVal
myObject As Object)
Dim myComparer As System.Collections.IComparer
Dim myIndex As Integer = myList.BinarySearch(1, 11, MyObject,
myComparer)
If myIndex < 0 Then
Console.WriteLine("The object to search for ({0}) is not
found. " _
+ "The next larger object is at index {1}.", myObject,
_
Not myIndex)
Else
Console.WriteLine("The object to search for ({0}) is at
index " _
+ "{1}.", myObject, myIndex)
End If
End Sub

Gives me an argument exception (guess because 'value' is not of the
same type as the elements of the ArrayList).

But neither does it work if I use:

FindMyObject(MyColliCol, "STUK")

I just want to be able to search through the arraylist (or a
collection) and use it as a converter between the integers and the
string. For instance when I search for 24 I want "DEUR" to be
returned..

If there is (hopefully an easier) way to do things like this, please
let me know.

I must admit this is getting way above my head...

Thanks in advance,

Mike

Mike,

You'll want to make your Colli class implement IComparable. You get the
ArgumentException with BinarySearch when (and I quote):

"Neither the value nor the elements of ArrayList implement the
IComparable interface"
--
Tom Shelton
MVP [Visual Basic]

[Jay B. Harlow [MVP - Outlook]]

Mike,

Dim myComparer As System.Collections.IComparer
Dim myIndex As Integer = myList.BinarySearch(1, 11, MyObject,
myComparer) You don't initialize myComparer before the call to BinarySearch. Did you
loose something in your example posted?
I just want to be able to search through the arraylist (or a
collection) and use it as a converter between the integers and the
string. For instance when I search for 24 I want "DEUR" to be
returned..
I would recommend using a HashTable, as it can be keyed by the integer

Dim MycolliCol As HashTable
MycolliCol.Add(1, New Colli(1, "STUK", 0))
MyColliCol.Add(16, New Colli(16, "ROL", 1))

Dim item As Colli
item = DirectCast(MycolliCol(1), Colli)
item = DirectCast(MycolliCol(16), Colli)
Hope this helps
Jay

"Mike Dole" <m_******@hotmail.com> wrote in message
news:fd**************************@posting.google.c om... I have an arraylist like the one with the Guitar Class sample in
Q316302.

Dim MycolliCol as arraylist
Private Sub FillArray()
MyColliCol.Add(New Colli(1, "STUK", 0))
MyColliCol.Add(New Colli(16, "ROL", 1))
MyColliCol.Add(New Colli(17, "BOS", 2))
MyColliCol.Add(New Colli(18, "DOOS", 0))
MyColliCol.Add(New Colli(19, "PAK", 0))
MyColliCol.Add(New Colli(20, "PANEEL", 0))
MyColliCol.Add(New Colli(21, "PALLET", 0))
MyColliCol.Add(New Colli(22, "BAK", 0))
MyColliCol.Add(New Colli(23, "PRES", 0))
MyColliCol.Add(New Colli(24, "DEUR", 0))
MyColliCol.Add(New Colli(25, "KAP/RAIL", 0))
End Sub
'I've placed the search in the form1_load for testing...

Private Sub Form1_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles MyBase.Load
FillArray()

Dim myObjectOdd As Object = New Colli(1, "STUK", 0)
FindMyObject(MyColliCol, myObjectOdd)

End Sub

Public Shared Sub FindMyObject(ByVal myList As ArrayList, ByVal
myObject As Object)
Dim myComparer As System.Collections.IComparer
Dim myIndex As Integer = myList.BinarySearch(1, 11, MyObject,
myComparer)
If myIndex < 0 Then
Console.WriteLine("The object to search for ({0}) is not
found. " _
+ "The next larger object is at index {1}.", myObject,
_
Not myIndex)
Else
Console.WriteLine("The object to search for ({0}) is at
index " _
+ "{1}.", myObject, myIndex)
End If
End Sub

Gives me an argument exception (guess because 'value' is not of the
same type as the elements of the ArrayList).

But neither does it work if I use:

FindMyObject(MyColliCol, "STUK")

I just want to be able to search through the arraylist (or a
collection) and use it as a converter between the integers and the
string. For instance when I search for 24 I want "DEUR" to be
returned..

If there is (hopefully an easier) way to do things like this, please
let me know.

I must admit this is getting way above my head...

Thanks in advance,

Mike

[Mike Dole]

Thanks everyone for your help.

Wouldn't know what to do without you guys!

Mike