Web Custom User Control Threw A Null Reference Exception?
Mar 8, 2010
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.
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'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.
[Code]....
I get the error when it gets to the last line here..
I have simple 3 tier web application and have mostly CRUDE functionalities. Recently I required to add new console application to the existing solution in which I call data layer methods for retrieving data from DB but I get an exception "The type initializer for threw an exception."When I debugged I found that the exception is thrown at datalayer on first line of class where I get connectionstring from
web.config, the code is public static readonly string CONNECT_STRING =
Now if I hardcode the connection string value like public static readonly string CONNECT_STRING = "Data Source=XYZ;uid=sa;password=XXX;initial catalog=ABC;"
it works fine.I don't understand what is the issue here as web application works fine with this datalayer.
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.
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:
[Code]....
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... [Code]....
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:
[Code]....
[Code]....
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.
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?
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:
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
[ServiceContract] public interface IBusiness { [OperationContract][code]....
Add client: [Code]....
But......... the result
Error:The server encountered an error processing the request. The exception message is 'The formatter threw an exception while trying to deserialize the message: Error in deserializing body of request message for operation 'UpdateLanguage'. The token '"' was expected but found '''.'. See server logs for more details. The exception stack trace is:
at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeRequest(Message message, Object[] parameters) at System.ServiceModel.Dispatcher.DemultiplexingDispatchMessageFormatter.DeserializeRequest(Message message, Object[] parameters) at System.ServiceModel.Dispatcher.UriTemplateDispatchFormatter.DeserializeRequest
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:
[Code]....
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:
All of a sudden I started getting this nasty exception all over the place:
The type initializer for 'System.Drawing.ToolboxBitmapAttribute' threw an exception.
Some relevant observations: * The error started occuring a few hours after the last deployment to the live server, not immediately after. So it basically started occuring of its own accord.
* We have recently moved to a new host (a VPS). The error only occurs on that server, not our local server nor at the old host's (which was a shared environment).
* The problem is basically the same as this: [URL]
* I tried reinstalling Ajax extensions, then our website in IIS, then finally the .Net 2 framework. But the error still occurs after all this.
* The error occurs on line 1, which is just the page directive: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="Test.WebForm1" %>
I'm finding it difficult to get a decent trace, but here is one that our CMS provided:
The type initializer for 'System.Drawing.ToolboxBitmapAttribute' threw an exception. at System.Web.UI.TemplateParser.ProcessException(Exception ex) at System.Web.UI.TemplateParser.ParseStringInternal(String text, Encoding fileEncoding) at System.Web.UI.TemplateParser.ParseString(String text, VirtualPath virtualPath, Encoding fileEncoding) at System.Web.UI.TemplateParser.ParseFile(String physicalPath, VirtualPath virtualPath) at System.Web.UI.TemplateParser.ParseInternal() at System.Web.UI.TemplateParser.Parse() at System.Web.Compilation.BaseTemplateBuildProvider.get_CodeCompilerType() at System.Web.Compilation.BuildProvider.GetCompilerTypeFromBuildProvider(BuildProvider buildProvider) at System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders() at System.Web.Compilation.BuildProvidersCompiler.PerformBuild() at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath) at System.Web.UI.TemplateControl.LoadControl(String virtualPath) at umbraco.macro.loadUserControl(String fileName, Hashtable attributes, page umbPage)
My own code doesn't use the ToolboxBitmapAttribute, but third party products like Peter Blum's and Telerik's do.
Peter Blum replied with some useful hints:
* The "type initializer" concept probably needs some research, but I'm guessing that is an important clue. A quick web search of "type initializer" finds many situations it occurs for a variety of classes.
* The stack trace suggests that this is happening as ASP.NET is compiling your web form. The error is happening as the ASP.NET parser runs. Again this is external from my code (even creating or "type initializing" the attribute is not something my code does).
i hve CRRedist2005_x86 installed in my ststem but still it give the below error
{"The type initializer for 'CrystalDecisions.CrystalReports.Engine.ReportDocument' threw an exception."} {"An error has occurred while attempting to load the Crystal Reports runtime.
Either the Crystal Reports registry key permissions are insufficient or the Crystal Reports runtime is not installed correctly.
I have a custom control that is based off the gridview control located at: here The control is basically a gridview that automatically creates a column of checkboxes that can be used to "check" individual rows in the gridview. During the gridview's "CreateColumns" event, the "checkboxcolumn" is created dynamically. The checkboxcolumn also contains another checkbox in the header that is used to "select/deselect all" checkboxes in the column. Since the gridview does not automatically remember the state of the checkboxes in the checkboxcolumn on postback, I added a method to the control called "SaveCheckBoxState" which stores the indexes of the checked rows in Viewstate, and then I modified the "OnRowDataBound" event to check the Viewstate and reset the checkboxes based on the Viewstate.
I then added a call to "SaveCheckBoxState" in the gridview's OnSorting and OnPageIndexChanging events. This works great so long as I'm sorting or changing pages. However, I need it to update the viewstate everytime someone clicks or unclicks one of the checkboxes. At this time, the checkboxes are rendered with an onclick event that calls some javascript to highlight the row, or in the case of the checkbox in the header, to select/deselect all checkboxes. I need to call the "SaveCheckBoxState" method from the javascript used by the customcontrol, or I need to find a way to modify viewstate from javascript and perform the same action as "SaveCheckBoxState".
I've tried adding the "SaveCheckBoxState" to the onclick event declaration in the checkboxes, but when run, it simply tells me that the method is undefined. It doesn't exist in the parent page, and I don't think I should have to make an event for the parent page to pass the click to. It seems to me this should be all self contained within the custom control. Does anyone know how I can acheive this? Here is the code for the gridview OnPreRender event where the onclick event of the checkbox is set:
protected override void OnPreRender(EventArgs e) { // Do as usual base.OnPreRender(e); // Adjust each data row foreach (GridViewRow r in Rows) { // Get the appropriate style object for the row TableItemStyle style = GetRowStyleFromState(r.RowState); // Retrieve the reference to the checkbox CheckBox cb = (CheckBox)r.FindControl(InputCheckBoxField.CheckBoxID); // Build the ID of the checkbox in the header string headerCheckBoxID = String.Format(CheckBoxColumHeaderID, ClientID); // Add script code to enable selection cb.Attributes["onclick"] = String.Format("ApplyStyle(this, '{0}', '{1}', '{2}')", SelectedRowStyle.CssClass, style.CssClass, headerCheckBoxID); // Update the style of the checkbox if checked if (cb.Checked) { r.BackColor = SelectedRowStyle.BackColor; r.ForeColor = SelectedRowStyle.ForeColor; r.Font.Bold = SelectedRowStyle.Font.Bold; } else { r.BackColor = style.BackColor; r.ForeColor = style.ForeColor; r.Font.Bold = style.Font.Bold; } } }
I have a web service which tries to connect to the SQL server.It uses Integrated security = true.I get the Conn.ServerVersion threw an exception of type System.InvalidOperationException as soon as the connection object is instatiated.
