Database Driven Nested Menu in ASP.Net LINQ

Question

Hi im trying to solve this problem, I'm fetching data from DB and create the menu:

  if (Context.User.IsInRole("Admin") == true)
  {


                mnMenu.Items.Clear();
                List<menuRole> menuParentList = new List<menuRole>();
                List<MenuItem> menuItemList = new List<MenuItem>();
                List<MenuItem> hoverItem = new List<MenuItem>();
                int parentPosition = 0;
                string menuName;

                menuParentList = roles.getMenuItems().ToList();

                for (int i = 0; i < menuParentList.Count; i++)
                {
                    if (menuParentList[i].menuType == "Admin")
                    {
                        if (menuParentList[i].MenuRole1 == "parent")
                        {
                            menuName = menuParentList[i].menuName.ToString();
                            menuItemList[i].Text = menuName;
                            parentPosition = i;
                        }
                        else if (menuParentList[i].MenuRole1 == "child")
                        {
                           hoverItem[i].Text = menuParentList[i].menuName;
                           hoverItem[i].NavigateUrl = menuParentList[i].MenuLink;
                           menuItemList[i].ChildItems.Add(hoverItem[i]);
                        }
                    }
                }
                mnMenu.Items.Add(menuItemList[0]);
                mnMenu.Items.Add(menuItemList[1]);
                mnMenu.Items.Add(menuItemList[2]);

      }

now its giving me this exception at the moment:

System.ArgumentOutOfRangeException was unhandled by user code
  Message=Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
  Source=mscorlib
  ParamName=index
  StackTrace:
       at System.ThrowHelper.ThrowArgumentOutOfRangeException()
       at System.Collections.Generic.List`1.get_Item(Int32 index)
       at PresentationLayer.UserControls.Menu.Page_Load(Object sender, EventArgs e) in C:\Users\Kurt\documents\visual studio 2010\Projects\aaa\PresentationLayer\UserControls\Menu.ascx.cs:line 44
       at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e)
       at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
       at System.Web.UI.Control.OnLoad(EventArgs e)
       at System.Web.UI.Control.LoadRecursive()
       at System.Web.UI.Control.LoadRecursive()
       at System.Web.UI.Control.LoadRecursive()
       at System.Web.UI.Control.LoadRecursive()
       at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
  InnerException:

menuItemList[i].Text = menuName; this adds the name of the parent header. — Mazda
– Mazda, Commented Dec 31, 2011 at 11:57

Henk Holterman · Accepted Answer · 2011-12-31 12:11:10Z

1

Well , this seems to make a few (too many) assumptions:

  mnMenu.Items.Add(menuItemList[2]);

You should check how many items you got.

if (menuParentList[i].MenuRole1 == "parent")
{
  menuName = menuParentList[i].menuName.ToString();
  menuItemList.Add(new MenuItem());  // add this 
  menuItemList[i].Text = menuName;
  parentPosition = i;
}

And the same for HoverItem .

Edit, take 3.

You cannot use i to index the menuList and hoverItem collections, they don't grow every step.

    if (menuParentList[i].MenuRole1 == "parent")
    {
        menuName = menuParentList[i].menuName.ToString();
        var newItem = new MenuItem();
        newItem.Text = menuName;
        menuItemList.Add(newItem);                             
        parentPosition = menuItemList.Count-1;   // flaky
    }
    else if (menuParentList[i].MenuRole1 == "child")
    {
        var newItem = new MenuItem();
        newItem.Text = menuParentList[i].menuName;
        newItem.NavigateUrl = menuParentList[i].MenuLink;
        hoverItem.Add(newItem);                             

        //menuItemList[i].ChildItems.Add(hoverItem[i]);
        menuItemList[parentPosition].ChildItems.Add(newItem);  // I think
    }

edited Dec 31, 2011 at 12:11

answered Dec 31, 2011 at 11:53

Henk Holterman

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6 Comments

Mazda Over a year ago

Im getting the error at this line of code : menuItemList[i].Text = menuName;

Henk Holterman Over a year ago

Right, I spotted it. See Edit.

Mazda Over a year ago

well it worked fine for the parent but over the hover item still gives the same error :S else if (menuParentList[i].MenuRole1 == "child") { hoverItem.Add(new MenuItem()); hoverItem[i].Text = menuParentList[i].menuName; hoverItem[i].NavigateUrl = menuParentList[i].MenuLink; menuItemList[i].ChildItems.Add(hoverItem[i]); }

Henk Holterman Over a year ago

Correct, I'll change my answer.

Mazda Over a year ago

Worked just fine just some minor changes thanks! youre the best!!

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