Why is my DataSet no Recognising Update

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VB

Hi folks,

I created data layer class for typed dataset in vb.net 2010 and used my Presentation tier.
Everything works fine but one problem. When I make changes(adds, edits, deletes) to the instance(ie dsDis) of the data layer dataset in the presentation layer and
I call HasChanges method against dsDis, it returns false value.

I have include the entire code for both presentation and data layer.

I have spent several hours fix the problem but to no avail, please I need help.

Thanks in advance for your assistance.

The code are show below, first the presentation

Public Class frmAddDistrict
    Dim claDis As claDataLayer
    Dim dsDis As diaby_certDataSet
    Dim WithEvents newDistrict As BindingSource
    Private Shared anInstance As frmAddDistrict
    Public Shared ReadOnly Property instance As frmAddDistrict
        Get
            If anInstance Is Nothing Then
                anInstance = New frmAddDistrict
            End If
            Return anInstance
        End Get
    End Property
    Private Sub frmAddDistrict_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
        anInstance = Nothing
    End Sub
    Private Sub frmAddDistrict_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        claDis = New claDataLayer
        dsDis = claDis.getDataSet
        Try
            newDistrict = New BindingSource
            With newDistrict
                .DataSource = dsDis
                .DataMember = "district"
            End With
            txtDistrictCode.DataBindings.Add("text", newDistrict, "d_code", True, DataSourceUpdateMode.OnValidation)
            txtDistrictName.DataBindings.Add("text", newDistrict, "name", True, DataSourceUpdateMode.OnValidation)
            txtLocation.DataBindings.Add("text", newDistrict, "location", True, DataSourceUpdateMode.OnValidation)
            cboRegion.DataBindings.Add("text", newDistrict, "region", True, DataSourceUpdateMode.OnValidation)

            Me.DataGridView1.DataSource = newDistrict

            newDistrict.AddNew()

        Catch ex As Exception

        End Try
    End Sub
    Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
        Try
            If btnAdd.Text = "&Save" Then
                If dsDis.HasChanges Then
                    newDistrict.EndEdit()
                    claDis.upDataSet(dsDis)
                    dsDis.AcceptChanges()
                    newDistrict.AddNew()
                End If
            End If
        Catch ex As Exception

        End Try
    End Sub
    Private Sub btnCancel_Click(sender As Object, e As EventArgs) Handles btnCancel.Click
        newDistrict.CancelEdit()
        Me.btnAdd.Text = "&Add"
        Me.Text = "Add New Districts"
        Me.btnCancel.Enabled = False
    End Sub
    Private Sub newDistrict_AddingNew(sender As Object, e As System.ComponentModel.AddingNewEventArgs) Handles newDistrict.AddingNew
        Me.btnAdd.Text = "&Save"
        Me.Text = Me.Text & " - Adding"
        Me.btnCancel.Enabled = True
        'Me.DataGridView1.
    End Sub
End Class

Data Layer:

Public Class claDataLayer
    'declare class level tableadapters
    Private taDistricts As diaby_certDataSetTableAdapters.districtTableAdapter
    Private taStaff As diaby_certDataSetTableAdapters.staffTableAdapter
    Private taSecurity As diaby_certDataSetTableAdapters.securityTableAdapter
    Private taYield As diaby_certDataSetTableAdapters.yieldsTableAdapter
    Private taFarms As diaby_certDataSetTableAdapters.farmsTableAdapter
    Private tafarmers As diaby_certDataSetTableAdapters.farmersTableAdapter

    'declare class level dataset
    Private dsDiabyDataSet As diaby_certDataSet

    'declare class level relation
    Private DistrictToStaff As DataRelation
    Private FarmersToFarms As DataRelation
    Private FarmsToYield As DataRelation
    Private StaffToFarmers As DataRelation
    Public Sub New()
        Try

            'instantiate tableadapters and dataset
            taDistricts = New diaby_certDataSetTableAdapters.districtTableAdapter
            taStaff = New diaby_certDataSetTableAdapters.staffTableAdapter
            taSecurity = New diaby_certDataSetTableAdapters.securityTableAdapter
            taYield = New diaby_certDataSetTableAdapters.yieldsTableAdapter
            taFarms = New diaby_certDataSetTableAdapters.farmsTableAdapter
            tafarmers = New diaby_certDataSetTableAdapters.farmersTableAdapter
            dsDiabyDataSet = New diaby_certDataSet

            'relation
            DistrictToStaff = dsDiabyDataSet.Relations!staff_district
            FarmersToFarms = dsDiabyDataSet.Relations!farms_farmers
            FarmsToYield = dsDiabyDataSet.Relations!yields_farms
            StaffToFarmers = dsDiabyDataSet.Relations!staff_farmers

            'fill dataset, fill parent first
            taDistricts.Fill(dsDiabyDataSet.district)
            taStaff.Fill(dsDiabyDataSet.staff)
            taSecurity.Fill(dsDiabyDataSet.security)
            taYield.Fill(dsDiabyDataSet.yields)
            tafarmers.Fill(dsDiabyDataSet.farmers)
            taFarms.Fill(dsDiabyDataSet.farms)

        Catch ex As Exception
            MessageBox.Show(ex.Message, Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub
    Public Function getDataSet() As diaby_certDataSet
        Return dsDiabyDataSet
    End Function
    Public Sub upDataSet(ByVal ds As diaby_certDataSet)
        Try
            'save child deletes
            If ds.yields.GetChanges(DataRowState.Deleted) IsNot Nothing Then
                'get the changes(deleted)
                Dim YieldDeletedTable As diaby_certDataSet.yieldsDataTable = CType(ds.yields.GetChanges(DataRowState.Deleted), diaby_certDataSet.yieldsDataTable)
                'execute the changes
                taYield.Update(YieldDeletedTable)
            End If

            If ds.farms.GetChanges(DataRowState.Deleted) IsNot Nothing Then
                'get the changes(deleted)
                Dim FarmsDeletedTable As diaby_certDataSet.farmsDataTable = CType(ds.farms.GetChanges(DataRowState.Deleted), diaby_certDataSet.farmsDataTable)
                'execute the changes
                taFarms.Update(FarmsDeletedTable)
            End If

            If ds.farmers.GetChanges(DataRowState.Deleted) IsNot Nothing Then
                'get the changes(deleted)
                Dim FarmersDeletedTable As diaby_certDataSet.farmersDataTable = CType(ds.farmers.GetChanges(DataRowState.Deleted), diaby_certDataSet.farmersDataTable)
                'execute the changes
                tafarmers.Update(FarmersDeletedTable)
            End If

            If ds.staff.GetChanges(DataRowState.Deleted) IsNot Nothing Then
                'get the changes(deleted)
                Dim StaffDeletedTable As diaby_certDataSet.staffDataTable = CType(ds.staff.GetChanges(DataRowState.Deleted), diaby_certDataSet.staffDataTable)
                'execute the changes
                taStaff.Update(StaffDeletedTable)
            End If

            'update parent rows
            If ds.security.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)) IsNot Nothing Then
                taSecurity.Update(ds.security)
            End If
            If ds.district.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)) IsNot Nothing Then
                taDistricts.Update(ds.district)
            End If

            'child adds and edited
            If ds.yields.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)) IsNot Nothing Then
                'get the changes(deleted)
                Dim YielAddsEddit As diaby_certDataSet.yieldsDataTable = CType(ds.yields.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)), diaby_certDataSet.yieldsDataTable)
                'execute the changes
                taYield.Update(YielAddsEddit)
            End If

            If ds.farms.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)) IsNot Nothing Then
                'get the changes(deleted)
                Dim FarmsAddsEdit As diaby_certDataSet.farmsDataTable = CType(ds.farms.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)), diaby_certDataSet.farmsDataTable)
                'execute the changes
                taFarms.Update(FarmsAddsEdit)
            End If

            If ds.farmers.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)) IsNot Nothing Then
                'get the changes(deleted)
                Dim FarmersAddsEdit As diaby_certDataSet.farmersDataTable = CType(ds.farmers.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)), diaby_certDataSet.farmersDataTable)
                'execute the changes
                tafarmers.Update(FarmersAddsEdit)
            End If

            If ds.staff.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)) IsNot Nothing Then
                'get the changes(deleted)
                Dim StaffAddsEdits As diaby_certDataSet.staffDataTable = CType(ds.staff.GetChanges(CType(DataRowState.Added + DataRowState.Modified, DataRowState)), diaby_certDataSet.staffDataTable)
                'execute the changes
                taStaff.Update(StaffAddsEdits)
            End If

        Catch ex As Exception
            MessageBox.Show(ex.Message, Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try

    End Sub


End Class