VS 2005 - Help displaying contents of ArrayList

[HawkeyeD]

Hello all,

I am having a problem displaying a custom array list I have in my code. (BTW. It is 1am where I am. I have been at this for a long time so I apologize if I don't make a lot of sense).

I built an arraylist of objects from a custom class. The arraylist contains 2 columns\dimensions.
The first is type string, the second decimal.

I am now attempting to take my arraylist and display it in my form. I have tried using a listview and iterating through it, but unsure of how to split the two columns up. I have tried something similar to the following I found in another forum:

            For i As Integer = 0 To arSearchArray.Count - 1
                Dim item As String = CType(arSearchArray(i), String)
                Dim arrItem() = Split(item, "___")
                Dim url As String = arrItem(0)
                Dim weight As String = arrItem(1)
                Dim lstItem As New ListViewItem(url, 0)
                lstItem.SubItems.Add(weight)
                lstSearchResults.Items.Add(lstItem)

            Next

but of course because the arraylist is a custom list it doesn't like me trying to cast it as a string. Plus I don't know if my split delimiter would work. Again, that is not my code, but code I found on another site.

I then tried a datagridview. But unsure about how to proceed. I created my datagridview on my form, but when I bind nothing happens. I know I am missing something as I am sure I will need more than just

dgSearchResults.DataSource = arSearchArray

however, my brain has decided to shut down now and so I will see if someone else much smarter\experienced then me can help out.

Please don't suggest I try and store my data in something else than the arraylist as I have written a lot of code around this including custom sorting code and going back to the drawing board is not an option (this is for a school project due soon).


Thanks again in advance.

[HawkeyeD]

Sorry this may be a long post, but I appreciate your patience with my descriptions of my problem.

Hi so after a couple of hours of sleep I am back at it again...sigh.

I know how to put a Dataset into a listview so I thought hey, let's convert the ArrayLIst to a Dataset and go from there. Not sure if I am on the right track but here is what I tried.

        Dim arSearchArray As ArrayList
        Dim var As CustomArray
        Dim dsArraySet As New DataSet
        Dim dtArrayTable As New DataTable
        Dim drArrayRow As DataRow

            dsArraySet.Tables.Add(dtArrayTable)
            dsArraySet.Tables(0).Columns.Add("URL", GetType(String))
            dsArraySet.Tables(0).Columns.Add("Term Weight", GetType(Decimal))

            For i As Integer = 0 To arSearchArray.Count - 1
                For Each var In arSearchArray(i)                               '<-- Breaking Here!!!!
                    drArrayRow = dsArraySet.Tables(0).NewRow
                    drArrayRow(0) = var
                    dsArraySet.Tables(0).Rows.Add(drArrayRow)
                Next
            Next

When it gets to the point I have indicated above I receive the error: Unable to cast object of type 'URL_Search.CustomArray' to type 'System.Collections.IEnumerable'

A little bit more background on my application. This is an Information Retrieval project for my Advanced Database class at University. I have a DB that contains webpage urls and the words in their body.

The user searches for a word, the app queries the DB for URLs that contain the word. The arraylist then is populated with the URL and the TermWeight of that URL (Vector Space Model).

In order to search the arraylist I built a custom array class. Here is the code for the class:

Public Class CustomArray
    Implements IComparable

    Public URL As String
    Public termWeight As Decimal

    Public Function CompareTo(ByVal obj As Object) As Integer Implements System.IComparable.CompareTo
        If Not TypeOf obj Is CustomArray Then
            Throw New Exception("This is not a correct type of object for the array")
        End If

        Dim Compare As CustomArray = CType(obj, CustomArray)
        Dim result As Integer = Me.termWeight.CompareTo(Compare.termWeight)

        If result = 0 Then
            result = Me.termWeight.CompareTo(Compare.termWeight)
        End If

        Return result

    End Function
End Class

Here is how the arraylist is populated:

'NOTE above this code is a call to the DB to get the URLs that the search term is located in
            Do While sqlReader.Read
                Dim arrObject As CustomArray = New CustomArray

                arrObject.URL = sqlReader("address")

                'Need to go and calculate the Vector and put it into the array
                tmpTermWeight = getVector(arrObject.URL.ToString)
                arrObject.termWeight = tmpTermWeight
                arBuildArray.Add(arrObject)
            Loop

So farther down I sort the arraylist based on the termweight calculated.

So I now have this arraylist based on a custom class. I need to get it to my form.

What are your suggestions? Bind to DatagridView? ListView? Some other method?

I appreciate your help and apologize for this long post.


Dave

[dglienna]

I think that LINQ would help you greatly.

http://msdn.microsoft.com/en-us/vbasic/bb688088.aspx