Disable/Hide Navigationmenu items of MasterPage

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Hi,
I have one navigationmenu on my masterpage. Whenever a user logins, the navigationmenu should display the menuitems as per the users permission.

eg: i have three navigationmenu items i.e. menuitem1, menuitem2, menuitem3.
a normal user has access only to two menuitems i.e. menuitem1 and menuitem2. And the third menuitems is either disable or hidden to him.

So when a user logins, he can only see two menuitems i.e. menuitem1 and menuitem2.
My Program: wht I did is I wrote user authentication code on my login.aspx page
i.e.

If lbl.Text = "user" Then
nwperm()
Response.Redirect("Home.aspx")
end if

HERE nwperm is a function which i wrote in the class file located in App_Code folder.

Sub nwperm()
Dim mymenu As Menu = Master.FindControl("NavigationMenu")
Dim mymi As MenuItem = mymenu.FindItem("TechnicalSupport")
mymi.Enabled =True
end sub

Problem/error: "object reference cannot create an instance of an object."
Please help me.

Posted 17-Jan-12 2:47am

mirzamujib

Updated 17-Jan-12 2:56am

Prasad_Kulkarni

v2

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mirzamujib 17-Jan-12 9:10am

need help guys....

manognya kota 17-Jan-12 13:46pm

Is the class file a content web form? (Meaning is the file like aspx.cs which has inherits the master page)?

mirzamujib 18-Jan-12 1:37am

no, it don't inherits the master page.
Thanks..

manognya kota 18-Jan-12 2:23am

If it doesnt inherit ..it means that there is no menu object there..and hence the error.Correct me if iam wrong .Could you please give the page declarations of the aspx pages.

2 solutions

Solution 1

I think you are not much clear about it. What is your current Datasource to populate the Menu? Best approach is to allow menu item in DB according to User roles and fetch item based on logged in user role.

If you have hard coded approach then show/hide menu item when you are building it instead of find the control after the rendered on client side.

But if you still thinking to use same above approach then find the exact menu item id from View source page then try to find it.

Thanks

Posted 17-Jan-12 7:07am

Parwej Ahamad

Comments

mirzamujib 18-Jan-12 1:40am

Thanks for the reply...
I'll try it and let you know..

mirzamujib 18-Jan-12 2:28am

Hi,
I'm getting the error on my class file at line
Dim mymi As MenuItem = mymenu.FindItem("mymenuitemname")
Here error is " object reference not set to an instance of an object"
plz help me on this issue....

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manognya kota · Accepted Answer · 2012-01-17T07:49:00

Solution 2

Hi,

This is my understanding from your description.

You have
1.Master page say Masterpage.master
2.Mainmenu custom control on the master page. Say mainmenu.ascx
3.A login.aspx and and home.aspx

Try putting your code in mainmenu.ascx.cs file for enabling and disabling you menu according to the users.

And for the error, check whether the class file inherits the master page with the main menu.

See the below code for page declaratives and this works abolutely fine for me.

XML

Page declarative of master

<%@ Master Language="C#" AutoEventWireup="true" CodeFile="myMasterPage.master.cs" Inherits="myMasterPage" %>

<%@ Register TagName="myMainMenu" Src="~/myMainMenu.ascx" %>


Page declarative of home page
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Home.aspx.cs" Inherits="Home"
    MasterPageFile="~/myMasterPage.master" %>

<%@ MasterType VirtualPath="~/myMasterPage.master" %>

Page declarative of mainmenu
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="MainMenu.ascx.cs" Inherits="MainMenu" %>

In your case, as the lanuguage is VB.You will have VB there.

For comparing your session variable for role, please see that the if condition first checks for the not null/nothing and the session value.

Hope this helps.

Posted 17-Jan-12 7:49am

manognya kota

Updated 17-Jan-12 22:32pm

v3

Comments

mirzamujib 18-Jan-12 2:02am

Thanks kota,
I tried to write the code in my mainmenu.acx.cs page. But it wont help me.
can you suggest me how can i make possible to user has menuitems according to his permissions
Thanks again...

manognya kota 18-Jan-12 2:21am

when the user logs in , save the role of the user in a session variable.
According to the role you can enable/disable the menu items.

manognya kota 18-Jan-12 2:22am

-"I tried to write the code in my mainmenu.acx.cs page. But it wont help me."

Dint get you.Please elaborate.

mirzamujib 18-Jan-12 3:26am

thanks for your reply...
Actually i wrote the user authenticaion code on my login.aspx page and make a funtion in the class file which is stored in App-Code and calling that function from my login.aspx page.

In funtion i wrote the code following
Dim mymenu As Menu = Master.FindControl("NavigationMenu")
Dim mymi As MenuItem = mymenu.FindItem("TechnicalSupport")
mymi.Enabled = True
Why I wrote this code in class file becuase I want to call the above funtion whenever a user logins, so according to the appropriate users permission, menutimes of navigation menu disable/hide.

Thanks again

manognya kota 18-Jan-12 3:30am

Try putting this code

Dim mymenu As Menu = Master.FindControl("NavigationMenu")
Dim mymi As MenuItem = mymenu.FindItem("TechnicalSupport")
mymi.Enabled = True

in your main menu.ascx.cs pageload.

manognya kota 18-Jan-12 3:31am

Calling the function present in the app_Code folder will not work as the Mainmenu control is not present in the class.Hence the object cannot be refered.

mirzamujib 18-Jan-12 3:43am

yeah it throws me same error. but if i write the same code which you mentioned above on page load event (which is my masterpage load event), again it throws same error object reference not set to an instance of an object.

manognya kota 18-Jan-12 3:46am

Did you try that code from mainmenu page load?

can you post the page declaratives of your master page, mainmenu and login page?

mirzamujib 18-Jan-12 3:46am

Now really I dont knw why its so difficult to just control the menu items in asp.net. Please if you know other ways to solve this user permissions issue, kindly tel me..
Thanks again...

mirzamujib 18-Jan-12 3:50am

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

If Session("userroles") = "DC-Software" Then
Dim mymenu As Menu = Master.FindControl("NavigationMenu")
Dim mymi As MenuItem = mymenu.FindItem("TechnicalSupport")
mymi.Enabled = True
Response.Redirect("AdminHome.aspx")
end sub

This is the page load event of my masterpage.

Now for user authentication code its on my default page and following is the code

Dim str As String = "select * from userregistration where userid='" + Login1.UserName + "' and pwd ='" + Login1.Password + "' "
Dim cmd As New SqlCommand(str, con)
cmd.ExecuteScalar()

thanks...

manognya kota 18-Jan-12 3:51am

Not this. Post the first line in your aspx page.This code will not work as the menu elemnts are not there in your master page.Check this code by putting it in the mainmenu pageload event.

mirzamujib 18-Jan-12 3:53am

sory i dont get u.. mainmenu pageload means my default login.aspx page?
sory may be i irritates u, but plz let me know...

manognya kota 18-Jan-12 3:56am

In your aspx page, there is a first line starting with <%@ Page Language=. Post the line

manognya kota 18-Jan-12 3:57am

See my code below and it works absolutely fine for me.

Page declarative of master

<%@ Master Language="C#" AutoEventWireup="true" CodeFile="myMasterPage.master.cs" Inherits="myMasterPage" %>

<%@ Register TagName="myMainMenu" Src="~/myMainMenu.ascx" %>

Page declarative of home page
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Home.aspx.cs" Inherits="Home"
MasterPageFile="~/myMasterPage.master" %>

<%@ MasterType VirtualPath="~/myMasterPage.master" %>

Page declarative of mainmenu
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="MainMenu.ascx.cs" Inherits="MainMenu" %>

In your case, as the lanuguage is VB.You will have VB there.

mirzamujib 18-Jan-12 4:05am

I've one masterpage where my navigationmenu is there.
its page file is:
<%@ Master Language="VB" CodeFile="MasterPage.master.vb" Inherits="MasterPage" %>
And There is nothing like <%@ Register TagName

Now my default page which is my login.aspx page, its code line :

%@ Page Language="VB" MasterPageFile="~/MasterPage.master" AutoEventWireup="false" CodeFile="default.aspx.vb" Inherits="_Default" title="CPC" %>

But wht you mention main menu, I dont get it....

I appreciated for your help
Thanks again...

mirzamujib 18-Jan-12 3:59am

%@ Page Language="VB" MasterPageFile="~/MasterPage.master" AutoEventWireup="false" CodeFile="default.aspx.vb" Inherits="_Default" title="CPC" %>

manognya kota 18-Jan-12 4:04am

You dint add your menu to your master page.Are you able to see the menu when you execute your code without the permission code?

mirzamujib 18-Jan-12 4:10am

yes i can see the menu ..
you know this enabling and disabling menu working fine if i defined static users permission, like: if user=aaa and pwd=bbb then
Dim mymenu As Menu = Master.FindControl("NavigationMenu")
Dim mymi As MenuItem = mymenu.FindItem("TechnicalSupport")
mymi.Enabled = True
Response.Redirect("AdminHome.aspx")
else

disable.

But when I tried to read the permission from my database and wants to execute the pages according to the users permission, I'm suffering.

Thanks again Kota....

manognya kota 18-Jan-12 4:14am

I guess i got it.Just tell me whether your menu is present even in the login page?

If yes, then the session variable in your master page load is the cause for this error.when the login page is loading with the master page,the session variable would have been assigned yet.

mirzamujib 18-Jan-12 4:25am

yeah you are right, my menu is present in the login page as well.

manognya kota 18-Jan-12 4:22am

In your if condition when checking the value of user role,
check like:
if session isNot Nothing and Session("userroles") = "DC-Software" then
your code..

mirzamujib 18-Jan-12 4:26am

Where shall i keep this condition? either in login or master page??
Thanks a ton kota..

manognya kota 18-Jan-12 4:28am

same place where you have put your working code
if user=aaa and pwd=bbb then
Dim mymenu As Menu = Master.FindControl("NavigationMenu")
Dim mymi As MenuItem = mymenu.FindItem("TechnicalSupport")
mymi.Enabled = True
Response.Redirect("AdminHome.aspx")
else

disable....

Just where ever you are checking the user role..or any session, check whether the session is not nothing first and then your session value.

mirzamujib 18-Jan-12 4:58am

I tried by copying this code on every page and it works but this takes lot of space on each page. Is there any thing like in vb.net if we want to reuse the code just make a class file and call that class on every page by simply writing the name of the class

manognya kota 18-Jan-12 5:53am

Not on every page.You can write it in master page.

mirzamujib 18-Jan-12 6:41am

I dont have any master page, my default page is my loginpage and master page has only my navigation menu. Shall i create new page, because in my master page if i'm writing code its showing me same error " object reference...

Thanks again kota...

manognya kota 18-Jan-12 6:56am

Is it working when you put the code in all pages?

mirzamujib 18-Jan-12 7:37am

yeah its working if i put the code in all web pages...
thanks....

mirzamujib 18-Jan-12 4:30am

thanks a ton kota..
I'll try it and let you know the result...

mirzamujib 18-Jan-12 4:37am

I tried now, no error. but when it redirects me to the admin page, still menu items of navigation meny are disable...

Really this makes me crazy since yesterday...

Thanks kota for your help...