C# - DetailsView FindControl() Returns Null After Some Postbacks?
Jan 7, 2010
I've been working for a long time with GridViews and DetailsViews, but yesterday I've come across a new scenario, which I quite do not understand.
I have a GridView with ImageButton (CommandName="Insert") which will change the mode of the DetailsView to Insert. Afterwards I'll look for a DropDownList inside that DetailsView and add some items dynamically. Works fine, but one first the first time I press that ImageButton. If I click on "Cancel" in the DetailsView and press the ImageButton again, the .FindControl() Method returns null.
I've created this sample: (To make it run in your Visual Studio, just bind a DataSource to the DetailsView, otherwise it will not be rendered)
I have also tried using a ItemTemplate, and not a InsertItemTemplate, but this results in the same. After using the ChangeMode-Method the DetailsView.CurrentMode == InsertMode. The only thing I can think of is, that the markup is already generated for the ItemTemplate and changing the Mode to InsertMode can't affect the rendered markup, or something like this.
Why method FindControl() returns null on FormView until call DataBind(). After that it returns everything correctly? What workaround are there? Call DataBind() before first call of FindControl() ?
I have a UserControl that has some controls inside. I want to refer those controls after, in another postback. But when I try to get them the Controls property of my controls returns null. I'm working on vs2008.
Like the title says, when I try to get a control (HiddenField) using this.Parent.FindControl it returns an exception. Curiosly this only happens when I change the browser language to Italian, English but not Spanish (I'm from Argentina so everything in my computer is spanish).
I have a Gridview and when the edit button is clicked the details of that row is displayed using a detailsview. While displaying, I need to find a control in detailsView, and then bind it with a Datasource. First of All I'm not sure about the event to be used but have used DetailsView1_DataBound. However, if I have to find the control using: var control=(ControlType)DetailsView1.Findcontrol("ID"); Always returns null. May be I am not using the right event, and it couldn't find the control at that point.
I got a problem about finding controls in Edit/Insert Itemtemplate inside a DetailsView.Here is the code.I put a Label (id= "Label6") to test whether the findcontrol method works or not. Unfortunately, I almost tried every means but still coudn't find it.
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
When i go to my detailsview itemtemplate, the checkbox returns the value correct, but every time i update it, it always returns 0.I'm using a MySQL db and the type of "grabbelpas" is tinyint(1).If more code is needed just ask. But my other textboxes are updated correctly, it's just the checkbox that doesnt update well.
I have a very strange issue where SelectionList always returns NULL when i try check its Selected Item/Value. I Googled a bit and I found out that when i click the submit button, the page is being refreshed and the SelectionList is being data bound again so it will revert back to its original behavior.
Then i tried enclosing the binding code in the Page_Load event in a !IsPostBack but still when i try to access the Selected property it is null and an exception is thrown.
My code goes something like this... (the braces are not matched properly)
I am working on a mvc project, and having problem with json. i have created a demo project with list of colors
public JsonResult GetResult() { List<string> strList = new List<string>(); strList.Add("white"); strList.Add("blue"); strList.Add("black"); strList.Add("red"); strList.Add("orange"); strList.Add("green"); return this.Json(strList); } i am able to get these on my page, but when i try to delete one color, that is when i send the following using jquery function deleteItem(item) { $.ajax({ type: "POST", url: "/Home/Delete/white", data: "{}", contentType: "application/json; charset=utf-8", success: ajaxCallSucceed, dataType: "json", failure: ajaxCallFailed }); }
the controler action public JsonResult Delete(string Color) {} Color always returns null, even if i have specified "/Home/Delete/white" in the url. i know i am doing something wrong or missing something, but not able to find out what.
I have a class library which has my LINQ doc in it. I added a stored procedure and I get the following in my .dbml.layout :
[Code]....
I include a reference to the dll of the class library to my web project and I get an error about value being returned as int where I am trying to put contents into a datalist or similar.
Code in class that calls this SP :
[Code]....
So I switched code to the following in my dbml.layout document :
I have a DataTable for which a PrimaryKey constraint has been set to be a combination of an integer column and a datetime column. When I try to 'Find' a row by saying,
dtFunds.Rows.Find(iContainerIndex)
I get a null value. iContainerIndex has been defined as an object array of size 2 with the integer ID and date values in it.
When I set a breakpoint in my code, I see that the very same values are present in the datatable.
If I try to execute, DataTable.Select() method with the integer column filter, I get a result - but returns no result when called with the date column filter.
What am I doing wrong here? The very same DateTime value is present in the datatable.
I want to use multiple targets with my ModalPopUp extender. One of my buttons is set as target in the ModalPopup and the other one will use server-side code to show the ModalPopup.
Then I found this little tutorial on the ASP.NET AJAX site.But when I use $find("modalInform") in the pageLoad Javascript function (as defined in the tutorial at the bottom), I'm always getting a $find("modalInform") is null error.
This code is included in a usercontrol, the usercontrol is used in a ASPX page and this ASPX-page uses a MasterPage. I've noticed that if I'm using
<%= modalInform.ClientID %>
I'm getting a different value then defined in my HTML-source (propably because of the MasterPage?).
It seemed to be the right place to post to.My problem is that when I try to read registry key, I get null value, even if it exists (regedit shows it exists).Application is windows service with Log On As Local System and registry key im trying to read is in HKEY_LOCAL_MACHINESOFTWAREClassesCLSIDOn my development machine (x64 win7) it works fine. But in live server (x64 windows server 2008 r2) I get NULL.ese operating systems should have similar policies or does Local System on server 2008 have any restrictions i should know about?
When I browse to www.mysite.com/mycontroller/myaction/myid, everything works ok. But visiting www.mysite.com/mycontroller/myaction produces:Server Error in '/' Application.Object reference not set to an instance of an object.Description: 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.
I have a new webpage "smile.aspx" with the web method "GetDate" that returns "current date as string".
I am using JQuery to make a Ajax call to that method, Right now i am using ASP.NET Version 2.0[.NET Framework 2.0,Visual Studio 2005].
The parameter returned by the Sucess function seem to return "undefined" .anyone Techhy, quick look at the ajax request code below will answer my problem.
I have a file upload page with an AsyncFileUpload control. When the user browses to the file the upload control pulls the file into memory. I then have an Upload button which fires the following code to save the file to a database.
I am finding that if files are over about 500KB then the FileBytes property of the control simply returns null. This happens on my server but when running the app locally it runs through fine.
I'm not handling the OnUploadCompleted event as I need to user to complete further information before committing the file to database.
I have this in my web.config: httpRuntime maxRequestLength="10000"/>
private void UploadDocument(int mietID) { if (Page.IsValid) { if (mietID > 0)
I am facing an amazing problem in ASP.NET. I have a website with many sub directories. The sub directories have aspx and aspx.cs files but do not contain web.config files. I am using the web.config file of the parent directory for storing config items for the respective code files in sub directories. But when i m trying to read the web.config using ConfigurationManager.AppSettings[] with absolutely the correct keys, there's no value being returned. Most amazing fact is, this same code works fine in dev enviroment but not in staging.
