I am using a ScriptManager in my aspx page and when I run on the submit button within the page I am receiving a "Page cannot be null" error message. I have looked around but cannot find anything that deals with this. I am writing in C# using VS2008 with the latest .NET framework, and the ScriptManager is for two Infragistics controls for multiline purposes
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m getting this error again and again. i m also using the ajax modalpopup extender in my page ..
View 3 RepliesI'm using the MVC2 framework and one of my views has a bit of conditional logic that gets the Page.User.Identity object and does a comparison with other values to determine what to display.That all works fine on the initial page load, but when I make an AJAX call to get partial page updates (I'm doing this all manually with YUI3, not the .NET AJAX stuff) the Page.User object is always null.
View 1 RepliesI'm having problems with accessing querystring params in my page method. Everywhere I read it says you can access querystrings just fine, but when I try it just returns null, what's the problem?
same problem I found - [URL]
I have implemented a custom ErrorController with UnknownError Action returning the View "~/Error/UnknownError" (not inside the Shared folder).
I have also modified the web.config file and add in custom errors section the following[Code]....
Inside the UknonwnError page i would like to display some information concerning the error occured using the HandleErrorInfo.
To test the error handling mechanism, i throw a custom ApplicationEcxeption from my Home/About controller action that is handled via the HandleErrorAttribute on the controller level.
The result is to get another unhandled exception thrown from the UknownError page due to the fact that HandleErrorInfo model is null.
Very often i write code like:
<img class="hasMenu" src="<%= (Model.Image==null)?Url.Content("~/Content/NoImage.jpg"):Model.Image.standard %>"
alt="Main image" />
Is there any predefined function which could beauty this code? Something like: ValueOrDefault(Model.Image.standard,Url.Content("~/Content/NoImage.jpg"))
I want to extend the System.Web.UI.Page-class with some extra stuff.
In the ctor I need the value of a session-variable.
The problem is that the Session-object is null...
public class ExtendedPage : System.Web.UI.Page {
protected foo;
public ExtendedPage() {
this.foo = (int)HttpContext.Current.Session["foo"]; // NullReferenceException
}
}
If I move the part with the session-object into the Load-Event everything works fine...
public class ExtendedPage : System.Web.UI.Page {
protected foo;
public ExtendedPage() {
this.Load += new EventHandler(ExtendedPage_Load);
}
void ExtendedPage_Load(object sender, EventArgs e) {
this.foo = (int)HttpContext.Current.Session["foo"];
}
}
Why is the Session-object null in the first case??
If you click a button that takes you to a page using <a href....> is the session variable lost?
In VS testing the web app everything works perfect, but when it is pushed to production when the page is loaded the Session Variable is null?
I have setup my business object to have a create_date and edit_date members both datetime datatypes. My company want to display the create_date and edit_date fields in a gridview for each transaction. The problem i have is that after insterting a record it will have a valid create_date but no edit_date and when displayed in the gridview it defaults to datetime.minvalue (My default). How on earth do i show an empty field in my gridview for a null datetime field in the database?
I am using similar architecture to the Imar Spaanjaars example of a tiered solution. With a few small tweeks it has worked well for me for ages. I am passing a List<Database> to my object datasource which connects to my gridview.
I have 2 table Table A, Table B.
Table A - Parent Table
ID - Uniqueidentifier not null(PK)
Table B -Child Table
ID - uniqueidentifier null(FK, TableA)
I have a stored procedure to insert data into Table B, but when I tried to insert a null value into column ID of table B, this error came up:
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_tableB_tableA". The conflict occurred in database "database name", table "table A", column 'ID'.
The statement has been terminated.
The insert statement in asp.net is like so:
sqlcommand.parameter.add(New Sqlparameter("ID", Nothing))
I am guessing adding nothing to the null value column is the problem, but i don't know how to fix it... The INSERT statement conflicted with the FOREIGN KEY constraint "FK_tableB_tableA". The conflict occurred in database "database name", table "table A", column 'ID'.
Have created a Webform based on a master page.The code executes OK and sends data to the database, but inserts null values for all entries except the GetDate.
If I use exactly the same code in a new webform which isn't based on the master page, it inserts everything correctly.Here is a snippet from the form which uses the master page: -
<%@ Page Title="" Language="C#" MasterPageFile="~/SpeedDateMasterPage.master" %>
<script runat="server">
private void AddToDatabase(object source, EventArgs e) [code].....
I have created a masterpage where I require user login. The content pages are only displayed if the user is authenticated.
<LoggedInTemplate>
<asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
</asp:ContentPlaceHolder>
</LoggedInTemplate>
On my content page I have
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<asp:DropDownList ID="dropdown1" runat="server"></asp:DropDownList>
</asp:Content>
When run, I can successfully authenticate and then when I attempt to view this particular content page I get an error on the page load where I'm trying to populate the dropdownlist. The error I get is a Null Reference exception. I don't fully understand the page lifecycle of an asp.net page, but I also don't understand why the page compiles successfully and its only when run that I get this exception. It seems that the control is not created when the page_load command is called. How can I change the contents of a dropdownlist on page load of a content page that requires authentication?
I have logged in to the application and naviagate to Resource Editor page where it allows user to enter the value and saves to the resource file of the application.
After user clicks save button and navigate to different page the session value becomes null.
If the user navigate to different page without clicking save the session variable has its value
Im trying to use code provide in this link below.http://www.codeproject.com/KB/aspnet/MultipleTabWindows.aspxim trying to have the below code in my master page instead of adding to each page. it works if i add to each page, but when i add to ,master page the session value for "WindowName" is always null.how can i fix this?
<script language="javascript" type="text/javascript">if(window.name != "<%=GetWindowName()%>"){ window.name = "invalidAccess"; window.open("InvalidAccess.aspx", "_self");}</script>public string GetWindowName(){ return Session["WindowName"].ToString();}
I want to terminate an application stat or set value to null where user is leaving the page...
does anyone know how can I do that?
I have a problem with a SessionVariable. I will explain what is happening:
1. From the default.aspx I send Session["LoginByAdmin"] = "Dummy"; and then redirect to this page where I have the code below. So the Page_Load sees that this Session["LoginByAdmin"] != null and enter this page. This works fine !
2. In the Page_Load, I later fill a ListBox1 with foldernames.
3. With Button1_Click1, I will now delete the choosen Folder in the ListBox1 wich works fine the first time and the ListBox updates the new existing folders in the ListBox. (I have wrapped this inside an updatepanel)
The problems comes now when I try to delete a choosen folder in the ListBox1 the second time in a row. When I select a Folder in the ListBox1 and now Press Button1, I will be redirected to "Default.aspx". This meens that this code is running: (That meens that Session["LoginByAdmin"] == null and I have not set this to null anywhere. This is my big question how this variable can be = null here?
if (Session["LoginByAdmin"] == null)
Response.Redirect("Default.aspx");
break;
[Code]....
I am using dropdownlist in my view page with some values which will display corresponding ID(primary key of other table) in my database.If i leave my dropdownlist blank and save it in database then its showing null parameter error. Can you explain how to use this reference type to overcome this error
View 2 Repliesi am using the following in a stored procedure.
[code]....
[Code]....Handling NULL...Field not updating when NULL?
I've got a master page where I've created two content place holders ('menu content place holder' and 'main body content place holder'). I've placed several controls (drop down lists and a calendar) in one of these content place holders (the 'menu content place holder'). In my content page I've set the 'menu content place holder' to 'Default to Master page content'. In my 'main body content place holder' I've included several controls (table, labels) which depend on the user selected items in the 'menu content place holder'.
After including a reference in all the necessary places- like this:
DropDownList ddlList1 = Master.FindControl("ddlList1")
as
DropDownList;
I still get the following exception (this exception occurs in my content page):
An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details:System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
[Code]....
I have a user control with GridView. GridView template has label that suppose to get custom object value Name.
aspx:
<asp:Label ID="lblImage" runat="server" Text='<%# MyData.Name%>' />
cs:
public MyObject MyData;
During page loading MyData object is null, so I'm getting exception: "Object reference not set to an instance of an object.".
How to avoid the error?
I developed a page in VWD 2008 and it works perfectly locally, but when I deployed it on the server every Page.FindControl() call is causing the NullReference Exception "Object reference not set to an instance of an object. " Can anyone help me out? Code is below
[Code]....
How do I eliminate the error Using Menu.IncludeStyleBlock requires Page.Header to be non-null (e.g. <head runat="server" />). When I add runat=server, I lose my style sheet for the entire app. This beganb failing when I upgraded to vs 2010 and .net 4.0. Worked fine on vs 2008 + .net 2.0.
View 1 Replieschecking for null on aspx page
[Code]....
My Original Issue here:Help! I've got repository access in my MVC master page! Refactor time!What originated as a re factoring job to improve performance has revealed new issues. If I should keep this in my original question - feel free to delete this one, and rename the old one to something more relevant. I'm using an ActionFilter applied to a base controller to load some user-customized settings. My issue is that I save these settings in the filterContext.Controller.ViewData object but its coming through as null on my master page. Here is the relevant code:
Action Filter
[AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
public class StoreSettingsActionFilter : ActionFilterAttribute
[code]...
I've used the UrlRewriting.Net module for a couple years now without any problems in Windows XP and Windows 2003. I just recently upgraded my home PC to Windows 7 and started developing a new website.The plan was to use .html extensions and rewrite them to their .aspx counterparts using the UrlRewriting.Net module. Everything works flawlessly in VWD 2008, but when I try running it through IIS7 it is a different story.
When I try to access a page via the .html rewrite I can no longer access Page.User; it keeps returning null. If I hit the page using it's .aspx extension, Page.User is correctly populated. I should also mention that I have a LoginView controller in my Master Page and it suffers from the same symptoms: When accessing via .html extension it shows the AnonyousTemplate; When using .aspx extension it properly shows the LoggedInTemplate. I'm guessing the two are related.
[Note: I've also tried extensionless URLs and they exhibit the same problem]
The only way I've gotten it to work is to switch the application pool to Classic, which then requires me to add an ASP.Net ddl handler for the .html extension [otherwise it is handled by the StaticFileHandler and comes up as a 404 error]. However, I'd like my web app to run properly for people without having to fiddle around with IIS.So I am left with several questions:Does anyone have ideas as to why Page.User always equals null for .html => .aspx rewritten pages?
Why does it work in VWD 2008, but not IIS7?
What changed from IIS6 => IIS7 that could have caused this?
[Note: I just tried a .aspx => .aspx rewrite and it did not exhibit the problem. Not really what I want, but thought I should mention it.]
