Checkbox issue in Gridview

[dotnetrookie]

Hi
This is my 1st post.I have two checkbox columns in gridview binded through item template. The checkboxes are Category and Subcategory. I have actually removed the duplicate values in the 1st column so that Category is listed only once for the corresponding subcategories. Now I need to make sure that the all the subcategory checkboxes to be checked when the corresponding category checkbox is checked. The issue is that only the first subcategory is checked and the remaining subcategory checkboxes are unchecked as the duplicate category checkboxes are not visible. Can someone please help me out...

 
<asp:GridView ID="GridView1" runat="server" AllowPaging="False" AllowSorting="True"
        HorizontalAlign="Center" AutoGenerateColumns="False" DataSourceID="CatSource"
        Width="496px" CellPadding="4" ForeColor="#333333" GridLines="Vertical">
        <Columns>
        <%--    <asp:BoundField DataField="M_CATPAGES_CAT" />
            <asp:BoundField DataField="M_PAGES_PAGES" />--%>
            <asp:TemplateField>
                <HeaderTemplate>
                    <input type="checkbox" id="chkAll" name="chkAll" onclick="check(this)" />
                </HeaderTemplate>
                <ItemTemplate>
                    <asp:CheckBox ID="chkSelect" runat="server" Text='<%# Eval("M_CATPAGES_CAT") %>' AutoPostBack ="true" OnCheckedChanged ="subcat_selectedchanged"  />
 
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField >
                <ItemTemplate>
                     <asp:Label ID="lblcatid" runat="server" Text='<%#Eval("M_CATPAGES_ID") %>' Visible="true"></asp:Label>
                </ItemTemplate> 
            </asp:TemplateField>
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:CheckBox ID="chkSubcat" runat="server" Text='<%# Eval("M_PAGES_PAGES") %>'   />
 
                </ItemTemplate>
            </asp:TemplateField>
 
              <asp:TemplateField>
                     <ItemTemplate>
                    <asp:Label ID="lblsubcat" runat="server" Text='<%#Eval("M_PAGES_ID_PK") %>' Visible="true"></asp:Label>
 
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField >
                <ItemTemplate >
                <asp:Label ID="lblcatsubcatid" runat="server" Text='<%#Eval("M_PAGES_CATID") %>' Visible="true"></asp:Label>
 
                </ItemTemplate>
                </asp:TemplateField>
 
 
        </Columns>
    </asp:GridView>
 

 Protected Sub CheckDuplicateValue()
        Dim cbxCat1 As CheckBox = New CheckBox()
 
 
 
        Dim iValue As String = String.Empty
        For i As Integer = 0 To GridView1.Rows.Count - 1
            cbxCat1 = GridView1.Rows(i).FindControl("chkSelect")
            Dim strgdvVal As String = cbxCat1.Text.ToString()
            If (strgdvVal = iValue.ToString()) Then
                cbxCat1.Visible = False
            Else
                iValue = cbxCat1.Text
            End If
        Next
    End Sub
 
 Protected Sub subcat_selectedchanged(ByVal sender As Object, ByVal e As EventArgs)
        For i As Integer = 0 To GridView1.Rows.Count - 1
            Dim lablcat As Label = DirectCast(GridView1.Rows(i).FindControl("lblcatid"), Label)
            Dim lablsubcat As Label = DirectCast(GridView1.Rows(i).FindControl("lblcatsubcatid"), Label)
            Dim lablsbcat_catid As Label = DirectCast(GridView1.Rows(i).FindControl("lblcatsubcatid"), Label)
            Dim chkCat As CheckBox = DirectCast(GridView1.Rows(i).FindControl("chkSelect"), CheckBox)
            Dim chkSub As CheckBox = DirectCast(GridView1.Rows(i).FindControl("chkSubcat"), CheckBox)
            If lablcat.Text = lablsbcat_catid.Text Then
                If chkCat.Checked = True Then
                    chkSub.Checked = True
                Else
                    chkSub.Checked = False
                End If
            End If
        Next
    End Sub