Hi Team,

In My application using dropdown list 2 differente data source in side multiview control while assigning the datasouce time as i am getting " Object reference not set to an instance of an object." find the .aspx

<asp:MultiView ID="MultiView1" runat="server">
                                            <asp:View ID="vAccounting" runat="server">
                                                <%--<asp:Panel ID="pnlAccounting" runat="server">--%>
                                                <igrid:WebDataGrid ID="uwgAccounting" Height="420px" AutoGenerateColumns="False"
                                                    runat="server" Width="100%" EnableAjax="False" EnableDataViewState="false" EnableViewState="false"
                                                    EnableTheming="False" ItemCssClass="clsRowitem">
                                                    <Columns>
                                                        <igrid:UnboundField Header-Text="Tank" Key="TankNameTag" Header-CssClass="Headercaption">
                                                        </igrid:UnboundField>
                                                        <igrid:UnboundField Header-Text="Last Service Change" Key="TimeStamp" Header-CssClass="Headercaption"
                                                            Width="140px">
                                                        </igrid:UnboundField>
                                                        <igrid:GroupField Key="AP" Header-Text="Accounting Product" Header-CssClass="Headercaption">
                                                            <Columns>
                                                                <igrid:UnboundField Header-Text="Code" Key="ActgPrCode" Header-CssClass="Headercaption">
                                                                </igrid:UnboundField>
                                                                <igrid:UnboundField Header-Text="Description" Key="ActgPrDesc" Header-CssClass="Headercaption"
                                                                    Width="180px">
                                                                </igrid:UnboundField>
                                                            </Columns>
                                                        </igrid:GroupField>
                                                        <igrid:GroupField Key="APG" Header-Text="Accounting Product Group" Header-CssClass="Headercaption">
                                                            <Columns>
                                                                <igrid:UnboundField Header-Text="Code" Key="PrGroupCode" Header-CssClass="Headercaption">
                                                                </igrid:UnboundField>
                                                                <igrid:UnboundField Header-Text="Description" Key="PrGroupDesc" Header-CssClass="Headercaption"
                                                                    Width="150px">
                                                                </igrid:UnboundField>
                                                            </Columns>
                                                        </igrid:GroupField>
                                                        <igrid:UnboundField Header-Text="Chgd By" Key="ActgProductUser" Header-CssClass="Headercaption">
                                                        </igrid:UnboundField>
                                                    </Columns>
                                                </igrid:WebDataGrid>
                                                <%--</asp:Panel>--%>
                                            </asp:View>
                                            <asp:View ID="vPlanning" runat="server">
                                                <%--<asp:Panel ID="pnlPlanning" runat="server">--%>
                                                <igrid:WebDataGrid ID="uwgPlanning" CssClass="FrameStyle" Height="420px" AutoGenerateColumns="False"
                                                    runat="server" Width="100%" EnableAjax="False" EnableDataViewState="false" EnableViewState="false"
                                                    EnableTheming="False">
                                                    <Columns>
                                                        <igrid:UnboundField Header-Text="Tank" Key="TankNameTag" Header-CssClass="Headercaption">
                                                        </igrid:UnboundField>
                                                        <igrid:UnboundField Header-Text="Last Service Change" Key="TimeStamp" Header-CssClass="Headercaption">
                                                        </igrid:UnboundField>
                                                        <igrid:GroupField Key="AP" Header-Text="Accounting Product" Header-CssClass="Headercaption">
                                                            <Columns>
                                                                <igrid:UnboundField Header-Text="Code" Key="ActgPrCode" Header-CssClass="Headercaption">
                                                                </igrid:UnboundField>
                                                                <igrid:UnboundField Header-Text="Description" Key="ActgPrDesc" Header-CssClass="Headercaption">
                                                                </igrid:UnboundField>
                                                            </Columns>
                                                        </igrid:GroupField>
                                                        <igrid:GroupField Key="PP" Header-Text="Planning Product" Header-CssClass="Headercaption">
                                                            <Columns>
                                                                <igrid:UnboundField Header-Text="Group" Key="PlngGroup" Header-CssClass="Headercaption">
                                                                </igrid:UnboundField>
                                                                <igrid:UnboundField Header-Text="Subgroup1" Key="PlngSubgroup1" Header-CssClass="Headercaption">
                                                                </igrid:UnboundField>
                                                                <igrid:UnboundField Header-Text="Subgroup2" Key="PlngSubgroup2" Header-CssClass="Headercaption">
                                                                </igrid:UnboundField>
                                                            </Columns>
                                                        </igrid:GroupField>
                                                        <igrid:UnboundField Header-Text="Chgd By" Key="ActgProductUser" Header-CssClass="Headercaption">
                                                        </igrid:UnboundField>
                                                    </Columns>
                                                </igrid:WebDataGrid>
                                                <%--</asp:Panel>--%>
                                            </asp:View>
                                            <asp:View ID="viewTankProperties" runat="server">
                                                <%--<asp:Panel ID="pnlTankProPerties" runat="server">--%>
                                                <igrid:WebDataGrid ID="uwgTankProperties" CssClass="FrameStyle" Height="380px" AutoGenerateColumns="False"
                                                    runat="server" Width="100%" HeaderCaptionCssClass="HeaderCaptionClass" EnableAjax="False"
                                                    ItemCssClass="RowBackGround" EnableDataViewState="false" EnableViewState="false">
                                                    <Columns>
                                                        <igrid:UnboundField Header-Text="Tag" Key="TagName">
                                                        </igrid:UnboundField>
                                                        <igrid:UnboundField Header-Text="Property" Key="Name">
                                                        </igrid:UnboundField>
                                                        <igrid:UnboundField Header-Text="Value" Key="Value">
                                                        </igrid:UnboundField>
                                                        <igrid:UnboundField Header-Text="UOM" Key="UOM">
                                                        </igrid:UnboundField>
                                                    </Columns>
                                                </igrid:WebDataGrid>
                                                <%--</asp:Panel>--%>
                                            </asp:View>
                                        </asp:MultiView>

.Net code :

  Dim tankList As TankCollection = Nothing
            Dim actgProdList As ProductCollection = Nothing
            Dim tankObj As Tank = Nothing
            Try
                strTankName = tankName
                If TypeOf (dataObj) Is TankCollection Then 'If DataObj is TankCollection
                    tankList = CType(dataObj, TankCollection)
                ElseIf TypeOf (dataObj) Is ProductCollection Then 'If DataObj is ProductCollection
                    actgProdList = CType(dataObj, ProductCollection)
                ElseIf TypeOf (dataObj) Is Tank Then 'If DataObj is Tank
                    tankObj = CType(dataObj, Tank)
                End If
                'User Selected the Tank Properties from tank history operations
                If operId = 3 Then
                    'Bind the Tank Object tag list to Grid
                    uwgTankProperties.DataSource = tankObj.TagList()
                    uwgTankProperties.DataBind()
                    'Turn on View to show
                    Me.MultiView1.SetActiveView(viewTankProperties)
                Else
                    'for all other operation in Tank History and Tank Service changes
                    If DefaultTankCodeView.Equals("A") Then 'View is Accounting
                        'No Operation Selected or Daily Values operation selected

                        uwgPlanning.ClearDataSource()
                        uwgPlanning.Rows.Clear()
                        uwgAccounting.Rows.Clear()

                        If operId = -1 OrElse operId = 1 Then
                            uwgAccounting.DataSource = tankList
                        Else
                            'Recorded Values
                            uwgAccounting.DataSource = actgProdList
                        End If
                        uwgAccounting.DataBind()

                        'Turn on View
                        Me.MultiView1.SetActiveView(vAccounting)
                    ElseIf DefaultTankCodeView.Equals("P") Then 'View is Planning
                        'No Operation Selected or Daily Values operation selected

                        uwgAccounting.ClearDataSource()
                        uwgAccounting.Rows.Clear()
                        uwgPlanning.Rows.Clear()

                        If operId = -1 OrElse operId = 1 Then
                            uwgPlanning.DataSource = tankList
                        Else
                            'Recorded Values
                            uwgPlanning.DataSource = actgProdList
                        End If

                        uwgPlanning.DataBind()
                        'Turn on View
                        Me.MultiView1.SetActiveView(vPlanning)
                    End If
                End If

using cleardatasource(),row.clear() every thing still getting the error please share the solution

Thanks

Ranhganathan palanisamy