如何在母版页导航栏中隐藏元素 [英] How to hide an element in master page navbar

问题描述

我正在尝试根据用户角色在母版页中的 navbar 中隐藏菜单选项但是当我尝试调用该元素时，它给了我一个错误.

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.

这就是我所做的:

MasterPage

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>

然后在另一页

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

我还尝试添加 runat ="server" ，但仍然无法正常工作.

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

推荐答案

使用

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;

您还错过了以下行中的 runat ="server" :

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

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

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