如何将现有菜单项添加回已删除的ASP.NET C＃

Question

I am trying to add back an menu item once it has been removed. I have removed the item using the following code:

NaviMenu.Items.Remove(NaviMenu.Items[1]);

The ASP.NET project was created on the framework 4.5, and the project was also created in Visual Studio 2012.

The control is a ASP.NET menu control System.Web.UI.WebControls.Menu not to be confused with System.Windows.Forms.ContextMenuStrip Web menus and Windows forms menu are not the same, and have different properties.

I would also like to have the item restored back to the original position. The menu item is already in the menu by default. Is there anyway to restore the menu item with out having to re add everything back like the Navigation URL, Vaule, etc?

The idea is that menu items are removed when the page is loaded. After the user logs into the site, then some of the items in the menu would be added back for the user.

Answer 1

Edit: I was going down the wrong path, so I'm replacing the entire answer.

Ok, it does seem that System.Web.Ui.WebControls.MenuItem does not include an option to hide/unhide, although Menu does. This is really dumb.

There is no easy answer, and there are different ways to implement this. The main thing is that you're going to need to:

1) Keep a hold on the menu item object that you are removing. You can't only reference the object from the menu

2) Keep track of where in the menu each item goes.

So, my new strategy is this ... you should have a method responsible for creating your menu. It'll be like this ...

public class MyMenuItem
{
    public bool ShowWhenNotLoggedIn { get; set; }
    public System.Web.UI.WebControls.MenuItem MenuItem { get; set; }
}

List<MyMenuItem> MyMenuItems = new List<MyMenuItem>(); //Create all your menu items and put them in here before running the menthod below
void CreateMyMenu(bool IsUserLoggedIn)
{
    MyMenu.Items.Clear();
    foreach (MyMenuItem item in MyMenuItems)
    {
        if (item.ShowWhenNotLoggedIn || IsUserLoggedIn)
            MyMenu.Items.Add(item.MenuItem);
    }
}

So, what I like about this is that you don't constantly have to remember what order the items go in. You just clear and re-create the whole menu each time. It's slightly less efficient than only removing/adding the items where you want them, but it's easier to read and understand the code. I think the performance hit is worth making the code readable, but that's your decision to make.

Also note that this is sort of like State Pattern-lite. We've defined two states: Logged In and Not Logged In. We've defined those states on objects that are affected by those states (the menu items). So, once you've written this logic, you don't have to dwell on each menu item anymore. You just say declare that you're in a new state, and everybody updates themselves accordingly. If you have other logic that depends on logged in vs not logged in, you can follow this same thing to them.