creating class as datasource - Xtreme Visual Basic Talk

12-20-2004, 02:51 AM

Carrie

Contributor

Join Date: Nov 2002

Posts: 485

creating class as datasource

I am creating for my data entry forms a class which represents the data on the form (for example I have a personlisting class which will define the fields contained within a person record) - see code below

Code:

Imports System.Data.OleDb

Public Class PersonListing
    Inherits ReadOnlyCollectionBase

#Region "Load"

    Public Sub Load()
        Dim oCon As New OleDb.OleDbConnection(ConnectionString)
        Dim oCmd As New OleDb.OleDbCommand

        With oCmd
            .Connection = oCon
            .CommandType = CommandType.Text
            .CommandText = "Select * from tblPerson"
        End With

        oCon.Open()

        Try
            Dim oDr As OleDb.OleDbDataReader
            oDr = oCmd.ExecuteReader
            While oDr.Read
                innerlist.Add(New Person(CInt(oDr("ID")), CStr(oDr("Name")), CStr(oDr("Surname")), CStr(oDr("TelNr"))))

            End While
            
            oDr.Close()
        Catch ex As Exception
            MsgBox(ex.ToString())
        Finally
            oCon.Close()
        End Try

    End Sub

Then I want to display this list in my combo box by doing the following:

Code:

PersonListing.Load

With Combobox1
 .datasource = PersonListing
End with

I am getting an unhandled exception with complex data binding accepts as a data source either an IList or an IList source

Not sure where I go from here?

Last edited by Shurik12; 12-25-2004 at 04:29 PM.

12-28-2004, 06:03 AM

kreeben

Freshman

Join Date: Oct 2004

Posts: 35

I am not sure what is causing the exceptin. But by just skimming through your code serios doubts come to my mind from this statement:

Code:

.datasource = PersonListing

Your class is of the type PersonListing. If the DataSource should be of the type IList then your class should return an IList object. If you create a property in your class, GetList, which returns an IList, then you should be able to bind the data like this:

Code:

With Combobox1
 .datasource = PersonListing.GetList()
End With

01-02-2005, 10:23 AM

MKoslof

Cum Grano Salis

Retired Moderator
* Guru *

Join Date: Jul 2002

Location: Baltimore, Maryland

Posts: 14,636

In addition, you shouldn't be assigning the datasource to a public database connection class like so. If you want to have a public connection module thats fine, but you want to assign the datasource of your comboBox to a DataTable, ArrayList, or anything that implements IList. I suggest creating a class for your dataset, and pass the dataset class object to this datasource method.

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