i get a null reference exception for this code.//was trying to retrieve cookie, who's name is attached as query string.
string cookieName = Request.QueryString["CookieName"].ToString();
I have a class that derives from System.Web.UI.Page and have set my pages to derive from this custom page class instead of Page. At runtime, the controls are never initialized and throw a NullReferenceException. I've changed some class names and namespaces in the pasted code to protect the innocent. The only thing that I currently override in my PageBase is OnPreLoad and I do call the base.OnPreLoad. I'll eventually add more functionality to this PageBase but for now all that it has is this:
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I've tried putting this into a class library (with System.Web referenced) and I've also tried moving the class into the web application and had the same results either way. As another strange twist, I have another class with derives from PageBase called IndexPageBase and it doesn't have this problem:
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I'm getting a null reference exception whenever I try to databind this datatable to the Gridview. I know for sure that the datatable has data. I've checked it.
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I get the error when it gets to the last line here..
I have a TextArea html helper method I'm calling in a foreach loop. Basically, when I initially load the View it works fine, but when i reload the View and load postback data, the same TextArea throws a NullReferencException and yet the variable I'm using in the TextArea as the name of the TextArea is not null. I've attached a picture below for demonstration:
if it's difficult to see, the blue arrow below is pointing to the variable used to name the TextArea. Again, it works on initial load, but it errors out on postback when the page is reloaded. I'm not sure what's going on.
I am getting this exception even though no values to my knowledge are null, apart from the model.SuburbID itself.
Here is controller code for getting the suburbs:
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Here is the view code:
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I have a url like this:
http://www.somepage.com/main.aspx. In this page, when I click on a link it takes me to a page
http://www.somepage.com/cental.aspx?cid=200. So in the cental.aspx.cs page I did the following in the page load:
if(request.querystring["comp"].tostring() != null)
{
//do some thing [code].....
So I got an error like: object reference not set to an instance of reference.My problem is, I am using the same page. So when I go from some page, I will have "comp". but other times not. So when there is no "comp", how do I handle it in request.querystring?
My controller calls a class in my model which is getting data from a REST web service. The class in the model then passes the data back to the controller using an IList, like so:
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My problem is this: The data that is held in the IList isn't there until the user has done a search in the View, submiting a form. This is a basic search function with 2 textboxes and a submit button in a form. When the user clicks submit, the controller action is called, the web service is then called, and the data in the IList gets populated. The problem is that in the View I am using a strongly typed view and my model reference in the foreach loop throws a Null Reference Exception because there is no data in it, because a search has not been conducted yet...
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So, how can I have the above foreach loop in my view if there isn't any data in the model until a search has been conducted? Is there a better way that I should be doing this?
Essentially, what's the best method for passing data back to a view that is based on a form submittion?
We have a chart on a page that current is hard coded with test data, client likes and we are trying to now link to live data.I have tried different things in the code behind to build the url and keep getting Null Reference Exception even though when i debug the url is there and complete. I can take the value that i get in debug and paste directly to the browser and the chart works. so i know that im building the url correctly, but setting the .Src of the image in the page_load event doesnt seem to be the correct way to populate the image..Here is the complete link that is built in the code behind that is passed to the src of the image control.http://chart.apis.google.com/chart?hs=300x265&chd=s:bD&chdl=DVDs|DVDs+with+Scracthes&chdlp=b&chl=44|5&chma=40,60,0,40&chtt=DVD+Report&cht=p3&chco=751010|FFCC33 In the page load event i have the following:
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I place a break point on the line where i set the src and as i step thru everything is correct and the src is being populate with the correct link, but when i step past that line, then i get the null reference.Now why is it that i can paste that link to the browser and it works.. and if i hardcode that link in the image src on my aspx page and comment out the code behind it works there also..
I am using httpcontext.Current in one my action method and i created the ms test method for testing this action and also i created the Mock object for httpcontect,but when i am trying to run the MS test script i am getting null reference exception from the line which i am using httpcontext.current in the action method.
View 1 RepliesI 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 am getting the Null reference exception in
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also when I used the Quickwatch, I get this error message.
getElementById The name 'getElementById' does not exist in the current context
I am also using Master Pages.
This is my button event code
protected void ImageButton2_Click1(object sender, ImageClickEventArgs e)
{
string data = Server.UrlDecode(Request.QueryString["BehCode3"]);
string filename = System.IO.Path.GetFileName(fup1.PostedFile.FileName);
string filename1 = System.IO.Path.GetFileName(fup2.PostedFile.FileName);
string filename2 = System.IO.Path.GetFileName(fup3.PostedFile.FileName);
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let me see if I can explain this clearly. I have a gridview control
and I am trying to use the Edit function. In my gridview, there are numerous rows. I pick one to change and click Edit. I then see the boss name in my gridview and click "Change". When I click Change, I'm expecting two fields to appear, one is a label, the other is a DropDownList. I get this error when I click:
System.NullReferenceException was unhandled by user code
Message=Object reference not set to an instance of an object.
Source=App_Web_lzmklgbg
StackTrace:
at Training_TRManageOrg.LinkButton1_Click(Object sender, EventArgs e) in d:projectsediting.aspx.cs:line 108
at System.Web.UI.WebControls.LinkButton.OnClick(EventArgs e)
at System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument)
at System.Web.UI.WebControls.LinkButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)
at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
InnerException:
Gridview HTML:
<asp:TemplateField HeaderText="Director">
<EditItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("director") %>'></asp:Label>
<asp:LinkButton ID="LinkButton1" runat="server" OnClick="LinkButton1_Click">Change</asp:LinkButton>
<asp:Label ID="Label4" runat="server" Text="Director" Visible="False"></asp:Label>
-
<asp:DropDownList ID="DropDownList2" runat="server" DataSourceID="trDirector"
DataTextField="name" DataValueField="id" onselectedindexchanged="DropDownList2_SelectedIndexChanged"
Visible="False"></asp:DropDownList>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("director") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
Code Behind:
protected void LinkButton1_Click(object sender, EventArgs e)
{
DropDownList DropDownList1 = ((DropDownList)FindControl("DropDownList1"));
DropDownList1.Visible = true; // this line is where the exception occurs
Label3.Visible = true;
}
I figure I must be overlooking something so I'm asking what am I missing?
I am stuck into a problem, i have a user control ProductListing.ascx that contains ListView binded to an object datasource, SelectMethod and SelectCountmethod are provided as well. Everything works fine but the problem started when i add another user control declarativlly Filter.ascx in the productListing.ascx. I want to assign value to a public property MaxPrice in Filter.ascx. I am trying to set this property in the SelectMethod of ObjectDataSource. Usercontrol "Filter.ascx" throws null reference exception when i try to set its MaxPrice Property.
I tried to acced the usercontrol in Databind method of ListView , it is accessible here but viewstate is empty at this point, i saved the value in viewstate in SelectMethod of objectDatasource but i cant access viewstate in ListView Databind. Its empty. Its a simple code and no rewriting to viewstate elsewhere.
Important: My Codebehind files are in a seperate project and .ascx files in seperate project
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
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I' m using a web custom control to upload images and mark them as primary. all the flow is working fine but it fails to mark images as primary in a diffrent category(there are four categories in which we can load a image-,catalog,primary,misc).It works in - category but not in others when I debug it is failing at a condition in grey . If it is not an element of the Datalist item it would not even enter the loop. I' m lost and unable to find the reason.
View 2 RepliesNull Reference Exception was not handled by user Object Reference not set to instance of an object
View 2 Repliesi have null reference exception in grid view, in the
string s = ((Label)GridView1.FindControl("Label6")).Text;
i tryed this to e.Values["EventId"].ToString()
but still the some why is that?
the full code :
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I have a clear button and a textbox in an aspx page. I set the session variable in this page as
String str = Textbox1.Text;
Session["TypeIds"] = str;
and I clear the sessions in a clear button event as
Session["TypeIds"]=null;.
Then when the user types some value in the textbox ,on Response.Redirect on another aspx page, the session variable returns null values.It does not retain its session state. The session state has to be maintained in the next page. Is it because this clear button event and setting explicitly to null creates this problem?
On my development machine, the session state data is retained after a post back to the server. (XP VS 2008) (This is true if running from within VS or if running in browser with localhost.)On the deployed test server, the session state is blank in IE, but works in Firefox. (Svr 2003 IIS 6)Both machines are running the exact same code with the exact same imputs and same web.config. There is no code between the post backs that write to the session state.Newest addition to the server would be the consumption of a WCF web service. Could this be a symptom of something missing on the server(s) when trying to connect with WCF? I could not find any information other than installing the 3.0 framework. I have 3.5 SP1 installed on the test server.
View 2 Replieswhat are the possible cases/causes for a thread abort exception? and how can we re-produce the same scenario if such exceptions can only be found on live production environment?
is it possible to access session variables when such exceptions occur or will session variables also get flushed and no longer be available? if we are able to manage/handle such exceptions, then will our application will continue to provide us a log for success/failure case of any particular task/process from where it was stopped?
I need to create a small web application. The first thing I need to do is to develop the login, logout and user session management functionality. I wanted to use a masterpage and a usercontrol for this purpose. When a user open the page and IS LOGGED IN, the usercontrol should something like this:
"Hello Username! <a>Logout</a>"
And if he is NOT LOGGED IN, the Usercontrol should show something like this
"Login | Logout"
When he clicks on the Login Button the Login-page should be opened. How can I build a Usercontrol which does the above thing. (I have never build a usercontrol and used it in a masterpage before!) The second problem is a little bit komplexer: What happens if the user idles some times and after that time (for example 30minutes) comes back to his pc and wants to execute an action in the web application. Normally he should get an session timeout asp.net exception. I don't want that the user sees this asp.net errorpage, I want to redirect him to the Login Page and he should relogin and gets an error message shown something like "You were timed out. Please login again".
I am working on a asp.net 3.5 app. In the Global.asax in the Application_Error method, I am logging everthing to ddatabase (log4Net).
I have a session limit of 20 minutes. What happens when the user hits that limit and then clicks on the Submit Button of the app. ?Will that generate any exception? and will that exception be logged into my database as I am logging all exceptions in my Application_Error method.
When I try to save an object reference in a view state it tries to save the object content using serialisation. to save the object reference only to apply to this object instance after postback?
View 5 RepliesI have an app that worked perfectly in development (Visual Studio 2008 Dev Server/Vista), was setup to use cookieless sessions in the web.config, which worked fine. Now rolled out into production (win2003/IIS6) configured as a Virtual Directory. But I'm having Null session issues after a button click. The problem doesnt persist in FF but in IE8. I tried to change session state to cookies and cookieless (InProc) with no go.
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