Thread: Concat, Filter - dealing with Arrays

Hi there,

I am entering data from a database into an array, the data is entered into the array correctly from the database I think.

But the problem arises when I try and print out the contents of my array. I get no error but the message I have used for testing prints this:


Your result-System.Collections.Generic.List`1[System.String]

It should print the contents of my array, heres the code:

I think the error is something to do with this line:

LineOfText = String.Concat("-", ar)

Code:

    Private Sub multiple_dates()

        'open calendar information
        'todo move to module call()
        Dim connetionString As String
        Dim oledbCnn As OleDbConnection
        Dim oledbCmd As OleDbCommand
        Dim sql As String

        Dim i As Integer

        i = 0

        sql = ""
        'todo set password and user for database
        connetionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=H:\My Pictures\hotel_db.mdb;User Id=admin;Password=;"
        sql = "Select * from tbl_calendar"

        oledbCnn = New OleDbConnection(connetionString)

        Try
            'open and prepare connection
            oledbCnn.Open()
            oledbCmd = New OleDbCommand(sql, oledbCnn)
            Dim oledbReader As OleDbDataReader = oledbCmd.ExecuteReader()
            Do While oledbReader.Read

                'move dates from database to listbox
                'Dim d As Date = CType(oledbReader("date_from"), Date)
                'ListBox1.Items.Add(d.ToShortDateString())

                Dim cal_id As String

                Dim date_from As String

                Dim date_to As String

                Dim notes As String

                date_from = txtDateFrom.Text

                If oledbReader("date_from") = date_from Then

                    Dim ar As New List(Of String)

                    cal_id = oledbReader("cal_date_id")
                    ar.Add(cal_id)
                    cal_id = oledbReader("date_from")
                    ar.Add(date_from)
                    date_to = oledbReader("date_to")
                    ar.Add(date_to)
                    notes = oledbReader("notes")
                    ar.Add(notes)

                    Dim LineOfText As String

                    LineOfText = String.Concat("-", ar)

                    MsgBox("Your result" & LineOfText)

                End If
            Loop

            oledbReader.Close()
            oledbCmd.Dispose()
            oledbCnn.Close()
        Catch ex As Exception
            'get error message
            MsgBox(ex.GetType.Name & " : " & ex.Message)
        End Try

        'get supplier or customer unique id
        Call get_supp_cust()

        'get the booking id
        Call get_booking_id()

        'get event id and 
        Call get_event_id()

        'get address details if any
        Call get_address_details()

    End Sub

The function is called from a calendar control, when ever an event has more than one event/date attached - i would like the user to be able to see the contents of my array (each event on that date) and choose or dismiss the event details. Hope this makes sense, I guess the first problem is trying to get the array details to be printed correctly...

Code:

LineOfText = String.Join("-", ar.ToArray)

Concat simply does 's1 & s2' (where ar.ToString would display the type name)

excellent response as always , many thanks