Variable is always with value, when it should be null at certain times

Question

I have this code: This rptAprovaDocumento is a Repeater

public List<ENTSISRegistroPendencia> RegistrarPendencia()
{
    CheckBox vchkTornarObrigatorio = null;
    for (int i = 0; i < rptAprovaDocumento.Items.Count; i++)
    {
        vchkTornarObrigatorio = (CheckBox)rptAprovaDocumento.Items[i].FindControl("chkTornarObrigatorio");

        if (vchkTornarObrigatorio != null)
        {
            if (!vchkTornarObrigatorio.Checked)
            {
                ventRegPendencia.IcDocObrigatorio = 0;
            }
            else
            {
                ventRegPendencia.IcDocObrigatorio = 1;
            }
        }
        else
        {
            ventRegPendencia.IcDocObrigatorio = 0;
        }    
    }
}

How it works. This repeater has a table that lists these records. This checkbox appears in a certain situation. The first time the credit analyst will make his analysis he appears, with the word "Make It Mandatory". This is his text. When the analyst checks and returns to the stores, the shopkeeper can see this listed document that the analyst made mandatory. By uploading this document and returning it to the analyst, it now appears to the analyst no longer as a Checkbox (Make It Mandatory) plus two Radiobutton: Approve and Fail. Well, it turns out that in that position of "i" inside the Peater, the var vchkTornarObrigatorio should come NULL, right? I thought to nullify all variables at the end of the FOR, but I found it a bit tricky, because I already said I want the value of the var in the "i" position inside the Peater, according to the code posted. I think about initializing the var inside the FOR, but I also smell Gambi, I’m not sure. It’s a problem of logic and I ask for help from colleagues to solve this junk. How to nullify this var inside the for.

<asp:Repeater ID="rptAprovaDocumento" runat="server" 
        onitemdatabound="rptAprovaDocumento_ItemDataBound"> 
        <HeaderTemplate>
            <table width="1000">
                <thead>
                    <th width="400">
                        Tipos de documento
                    </th>
                    <th width="150">
                    </th>
                    <th>
                    </th>
                </thead>
        </HeaderTemplate>
        <ItemTemplate>
            <tr>
                <td>
                    <asp:HiddenField ID="hdfCdTipoDocumento" runat="server" Value='<%# Eval("CdTipoDocumento")%>' />
                    <asp:HiddenField ID="hdfCdPendencia" runat="server" Value='<%# Eval("CdPendencia")%>' />
                    <asp:HiddenField ID="hdfCdDocumento" runat="server" Value='<%# Eval("CdDocumento")%>' />
                    <asp:HiddenField ID="hdfIcAprovado" runat="server" Value='<%# Eval("IcAprovado")%>' />
                    <asp:HiddenField ID="hdfIcDocObrigatorio" runat="server" Value='<%# Eval("IcDocObrigatorio")%>' />
                    <asp:HiddenField ID="hdfCdMotivo" runat="server" Value='<%# Eval("CdTipoMotivoRecusa")%>' />

                    <%--<strong><a href="/UpLoads/<%# Eval("DsPathDocumento")%>" class="linkUpload"><%# Eval("NmTipoDocumento")%></a></strong>--%>

                    <strong><a <%# Eval("DsPathDocumento") != null && !String.IsNullOrEmpty(Eval("DsPathDocumento").ToString()) ? String.Concat("href='/UpLoads/", Eval("DsPathDocumento"), "'","class='linkUpload'") : "style='cursor: default; color:#000000;' class='disabled'" %>>
                        <%# Eval("NmTipoDocumento") %>
                    </a></strong>                      

                    <asp:Label ID="lblDtCriacao" Text='' runat="server" /><br />
                    <asp:Label ID="lblNmObrigatorio" Text='<%# Eval("NmTipoObrigatorio") %>' runat="server" Font-Bold="True" />
                </td>
                <td>
                    <asp:RadioButtonList ID="rbIctAprovado" CssClass="radiobuttonAprovaReprova" onclick="javascript:MostraEscondeControle(this);"
                        runat="server" AutoPostBack="false" TextAlign="left" RepeatColumns="0" RepeatDirection="Vertical"
                        CausesValidation="False" OnSelectedIndexChanged="rbIctAprovado_SelectedIndexChanged" RepeatLayout="UnorderedList">
                        <asp:ListItem Value="1">Aprovar</asp:ListItem>
                        <asp:ListItem Value="0">Reprovar</asp:ListItem>
                    </asp:RadioButtonList>
                    <asp:CheckBox ID="chkTornarObrigatorio" runat="server" Text="Tornar Obrigatório" />
                    <br />
                    <asp:DropDownList ID="cmbCdMotivoRecusa" runat="server" Enabled="false" AutoPostBack="false"></asp:DropDownList>
                    <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="É necessário aprovar ou reprovar este documento para prosseguir."
                        ControlToValidate="rbIctAprovado" ValidationGroup="grupoAprovaReprova" Text=""></asp:RequiredFieldValidator>

                </td>
            </tr>
        </ItemTemplate>
        <FooterTemplate>
            </table>
        </FooterTemplate>
    </asp:Repeater>

Answer 1

The command rptAprovaDocumento.Items[i].FindControl("chkTornarObrigatorio") as CheckBox simply returns the CheckBox chkTornarObrigatorio associated with the current item.

Like all the RepeaterItem have a CheckBox chkTornarObrigatorio, then it will be found in all the items of the interaction, idepedente it is invisible or disabled.

EDIT

As identified in conversation with the Questioner, we found a partial resolution.

then in this case you should check the Visible property, a chkTornarObrigatorio.Visible on the place of vchkTornarObrigatorio != null must solve