How to hide an element in master page navbar

Question

I'm trying to hide menu options from navbar in master page based on user roles but when I tried to call the element it gives me an error.

This is what I did :

MasterPage

<div class="navbar-collapse collapse">
    <ul id="MasterMenu" class="nav navbar-nav">
        <li id="liDashboard">
            <a runat="server" href="~/_Dashboard">Dashboard</a>
        </li>
        <li id="liTicket">
            <a runat="server" href="~/Forms/Tickets/_Ticket">Ticket+</a>
        </li>
        <li id="liReports">
            <a runat="server" href="-">Reports</a>
        </li>
    </ul>  
</div>

And in another page

if (User.IsInRole("User"))
{
    System.Web.UI.HtmlControls.HtmlGenericControl liDashboard = (System.Web.UI.HtmlControls.HtmlGenericControl)Master.FindControl("liDashboard");
    liDashboard.Visible = false;
}

Also I tried to add runat="server" but it still not working.

Error : System.NullReferenceException: 'Object reference not set to an instance of an object.' liDashboard was null. — Mohammad Sufian Al-Omar, Oct 25 '17 at 14:14
Try this answer https://stackoverflow.com/questions/11416959/c-sharp-error-using-findcontrol-on-div-id. Basically, you need to find your ContentPlaceHolder first and then find your control in it. — Roman K., Oct 25 '17 at 14:31

Salah Akbari · Accepted Answer · 2017-10-26T11:19:12.027

3

Use Null-Conditional operator (?.) and check for null before assignment:

System.Web.UI.HtmlControls.HtmlGenericControl liDashboard = 
     (System.Web.UI.HtmlControls.HtmlGenericControl)Master?.FindControl("liDashboard");
if (liDashboard != null) liDashboard.Visible = false;

Also you have missed runat="server" in the following line:

<li id="liDashboard" runat="server">

edited Oct 26 '17 at 11:19

answered Oct 25 '17 at 14:16

Salah Akbari

39,330
10
79
109

The code have no errors but the item still appears in the navbar. – Mohammad Sufian Al-Omar Oct 25 '17 at 14:20
@MohammadSaffarini Because You have missed `runat="server` for `liDashboard`. Check my updated answer. – Salah Akbari Oct 25 '17 at 14:26
still have the same here is your update '
Dashboard

Ticket+

Reports

'
– Mohammad Sufian Al-Omar Oct 25 '17 at 14:30
@MohammadSaffarini Also try to rebuild your project once. It should works fine if you do this steps. – Salah Akbari Oct 25 '17 at 14:44
I test it with response.redirect and it's working fine – Mohammad Sufian Al-Omar Oct 25 '17 at 14:48

score 0 · Answer 2 · edited Nov 02 '17 at 16:59

0

For example if your place holder something like that.

<asp:ContentPlaceHolder ID="MainContent" runat="server"/>

Try to use something like that

Master.FindControl("MainContent").FindControl("liDashboard")

Then find your value hierarchically

And of course values need to be with runat="server"

Edit

Give your PlaceHolder an ID

<asp:PlaceHolder ID="Something" runat="server"/> and get your value with:

Master.FindControl("Something").FindControl("liDashboard")

edited Nov 02 '17 at 16:59

Salah Akbari

39,330
10
79
109

answered Oct 25 '17 at 14:31

sonertbnc

1,580
16
26

Still same result System.Web.UI.HtmlControls.HtmlGenericControl liDashboard = (System.Web.UI.HtmlControls.HtmlGenericControl)Master?.FindControl("myDiv"). FindControl("MasterMenu").FindControl("liDashboard"); if (liDashboard != null) liDashboard.Visible = false; – Mohammad Sufian Al-Omar Oct 25 '17 at 14:43
put all master page here and please don't put any (?) null control .You need to get an error if null – sonertbnc Oct 25 '17 at 14:44
I'll put it as an answer – Mohammad Sufian Al-Omar Oct 25 '17 at 14:47
check the answer again – sonertbnc Oct 25 '17 at 14:49
still the same issue – Mohammad Sufian Al-Omar Oct 25 '17 at 15:01
all of this kind values with runat="server" and after that compile your code? – sonertbnc Oct 25 '17 at 15:02

How to hide an element in master page navbar

2 Answers2

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