Hello,
I set the DataSource property of a DropDownList to as DataSet that is filled
from a SQLDataAdapter. The AutoPostBack property of that DropDownList is set
to True. When the SelectedIndexChanged occurs, if I set a BreakPoint in the
event and I check the values in the Watch window, I can see that the
DataSource property still contain the DataSet. When I set the DataSource of
a DropDownList to my object collection and check the values in the Watch
window when the SelectedIndexChanged occurs, the DataSource is set to
Nothing. Why? What appen to my object? Is my object need something so that
the DataSource property of the DropDownList can retain my object collection?
Hope that someone can help me.
Here are some parts of my code of my object collection. I have a VTBCodes
class that is a collection. I allso have VTBCode class that represent the
data. VTBCodes inherits from PAICollectionBase and implements iEntitys.
PAICollectionBase inherits from CollectionBase of the .net framework.
VTBCode inherits from EntityBase. EntityBase implements iEntity.
<Serializable()> Public MustInherit Class PAICollectionBase
Inherits CollectionBase
Implements IDisposable
Public MustOverride Function Add(ByVal pObject As Object) As Integer
.....
End Class
Public Interface iEntitys
Function GetData() As iEntitys
....
End Try
<Serializable()> Public Class VTBCodes
Inherits PAICollectionBase
Implements iEntitys
Public Overrides Function Add(ByVal pEntity As Object) As Integer
If TypeOf (pEntity) Is VTBCode Then
....
Else
Dim ex As New Exception("...
Throw ex
End If
....
Public Overloads Function GetData() As PAIiFactory.iEntitys Implements
PAIiFactory.iEntitys.GetData
Dim oconConnection As System.Data.SqlClient.SqlConnection
Dim odrVTBCode As System.Data.SqlClient.SqlDataReader = Nothing
oconConnection = Me.GetConnection
Dim strSQL As String = "Select...
odrVTBCode = SqlHelper.ExecuteReader(oconConnection, CommandType.Text,
strSQL)
While odrVTBCode.Read
oVTBCode = New VTBCode
oVTBCode.Desc.Value =
odrVTBCode.Item(oVTBCode.Desc.AliasName(False))
list.Add(oVTBCode)
End While
Return Me
....
End Class
Public Interface iEntity
Sub UpdateData(ByVal pConnection As
System.Data.SqlClient.SqlConnection, ByVal pTrans As
System.Data.SqlClient.SqlTransaction)
Sub DeleteData(ByVal pConnection As
System.Data.SqlClient.SqlConnection, ByVal pTrans As
System.Data.SqlClient.SqlTransaction)
Sub InsertData(ByVal pConnection As
System.Data.SqlClient.SqlConnection, ByVal pTrans As
System.Data.SqlClient.SqlTransaction)
....
End Interface
Public MustInherit Class EntityBase
Implements iEntity
Implements IDisposable
Public MustOverride Function GetData(ByVal pExpressionCollection As
iExpression) As iEntity Implements PAIiFactory.iEntity.GetData
Public MustOverride Overloads Sub UpdateData(ByVal pConnection As
System.Data.SqlClient.SqlConnection, ByVal pTrans As
System.Data.SqlClient.SqlTransaction) Implements
PAIiFactory.iEntity.UpdateData
Public MustOverride Overloads Sub DeleteData(ByVal pConnection As
System.Data.SqlClient.SqlConnection, ByVal pTrans As
System.Data.SqlClient.SqlTransaction) Implements
PAIiFactory.iEntity.DeleteData
Public MustOverride Overloads Sub InsertData(ByVal pConnection As
System.Data.SqlClient.SqlConnection, ByVal pTrans As
System.Data.SqlClient.SqlTransaction) Implements
PAIiFactory.iEntity.InsertData
....
End Class
<Serializable()> Public Class VTBCode
Inherits EntityBase
Private mfldDescFr As FieldString
....
Public Sub New()
mfldDesc = New FieldString("Desc", Me, "Desc", 100)'Name , Me,
AlisaName, Length
...
End Sub
....
Public Property Desc() As FieldString
Get
Return mfldDesc
End Get
Set(ByVal Value As FieldString)
mfldDesc = Value
End Set
End Property
....
Public Overrides Function GetData(ByVal pExpressionCollection As
iExpression) As iEntity
....
Public Overrides Function ToString() As String
'This will show the value in the DropDownList
Return Convert.ToString(mfldDesc.Value)
End Function
....
End Class
This is the code to fill the DropDownList
Dim oVTBCodes As New VTBCodes
cboCodeDivision.DataSource = oVTBCodes.GetData
cboCodeDivision.DataBind()
