Web Forms :: Class Object Becomes NULL After PostBack
Feb 13, 2014
I have a asp.net page titled EstMaterials.aspx with a gridview that fills from a SQL table based on a parameter passed to it. The code for calling the form is below.
<asp:UpdatePanel ID="upAddMaterials" runat="server">
<ContentTemplate>
<div id="AddMaterials" style="text-align:center">
<asp:Button ID="btnDecoy" runat="server" Text="Decoy" style="display:none" />
<asp:LinkButton ID="lbAddMaterials" runat="server" Text="Add Materials"></asp:LinkButton>
[code]....
I have an a button field set as a link in a gridview. When the user clicks on the link it should open the "EstMaterials.aspx" page with a gridview listing the materials required for this job. If I do not have a parameter i.e, ScheduleWeek.oJob.JobSeqNbr, the gridview fills fine. However, with the parameter listed the gridview does not fill. It appears the form opens without ever looking at the parameter being passed.The page load event is below.
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
If Not IsNothing(ScheduleWeek.oJob) Then
Dim tbl As New DataTable
[code]....
View 1 Replies
Similar Messages:
Nov 19, 2010
I have a user control with a number of methods. I also have a dataset object that I'm filling in one method, but I also need to access that same dataset (and the data in it) in another.
I am filling the dataset from some xml that I get from a webservice when someone clicks on a button. The data from the dataset is then bound to a listbox control. When someone selects an item in the list control (I have autopostback set to true on it) it then fires off another method and it's this method where I need to access the data in the dataset, but when I check the immediate window it's telling me that the dataset is set to null.
Where am I going wrong?
[code]....
View 4 Replies
Sep 8, 2010
I've build a class like this:
[code]....
The values of this class are set at postback by clicking a radiobutton list. Problem however is I don't know how to save this values across multiple postbacks. I thought of using viewstate but I'm not quite sure how to do it with this class.
Maybe I'm missing some important thing here.
Hope someone can point me in the right direction.
View 4 Replies
Oct 5, 2010
i have created a user control UserControl.ascx, in Code behind file of UserControl.ascx i have created an object of a class MyClass.cs,
Like
if(!Page.IsPostback) {
objMyClass= new MyClass();
}
but when i click on button of UserControl.ascx page and try to access objMyClass object then it set as null, so how to persist MyClass object when page PostBack, i wanted to keep object persist till the user access the page, when user goes out of this page then object should distroy?
[code].....
View 9 Replies
Sep 16, 2010
I have this Control directive in a usercontrol (i've changed the namespace and class name):
<%@ Control Language="C#" AutoEventWireup="true" Inherits="Namespace.Path.To.ClassName" %>
<asp:TextBox runat="server" ID="txtComment" TextMode="MultiLine" ValidationGroup="comment" />
ClassName is a class that lives in a class library and this is the class:
namespace Namespace.Path.To
{
public class ClassName : System.Web.UI.UserControl
{
protected System.Web.UI.WebControls.TextBox txtComment;
protected void Page_Load(object sender, EventArgs e)
{
HttpContext.Current.Response.Write(txtComment == null);
HttpContext.Current.Response.End();
}
View 3 Replies
May 17, 2010
m getting this error again and again. i m also using the ajax modalpopup extender in my page ..
View 3 Replies
May 13, 2010
My site was woking fine, now i noticed that i get an error "Microsoft JScript runtime error: 'null' is null or not an object" when i checked the view source, i saw the following system generated code
<script type="text/javascript">
var Page_ValidationActive = false;
if (typeof(ValidatorOnLoad) == "function") {
ValidatorOnLoad();
function ValidatorOnSubmit() {
if (Page_ValidationActive) {
return ValidatorCommonOnSubmit();
}
else {
return true;
}
WebForm_AutoFocus('txtMailAddress');// --> IS THIS RIGHT???? out side the braces???
</script>
</form>
</body>
</HTML>
and a reference to this line below
<IFRAME id="__hifSmartNav" name="__hifSmartNav" style="display:none" src="/m2qa/WebResource.axd?d=fvL5WUdiCo1B4KvdiJfkfg2&t=633546432952161750"></IFRAME>
View 3 Replies
Jul 23, 2010
List New Class takes up memory?Do I need C=null; in the code below?
//class Category
public List<Category> SelectAll()
{
List<Category> LV = new List<Category>();
string command = "SELECT * from categories";
SqlCommand sc = new SqlCommand(command, new SqlConnection(GlobalFunction.Function.GetConnectionString()));
sc.Connection.Open();
SqlDataReader dr = sc.ExecuteReader();
using(dr)
{
[code]...
View 5 Replies
May 10, 2010
[code]....
this code give that solution.but if any one of the field have null(example:r.urrQuickLinkRights contain the NULL) then only it will throw error like Object reference not set to an instance of an object.
View 2 Replies
May 27, 2010
i have an application wherein i have incorporate a "Remember Me" feature for the login screen. I do this by creating a cookie when the user logs in for the first time, so next time when the user visits the site i get the cookie and load the user information.
i have written the code for loading user information in a common class in the App_Code folder...and all my pages inherit from this class.
code for loading the user info is as follows:
public static void LoadUserDetails(string emailId)
{
UsersEnt currentUser = UsersBL.LoadUserInfo(emailId);
if (currentUser != null)
HttpContext.Current.Session["CurrentUser"] = currentUser;
}
Now the problem is i get an "Object reference" error when i try to store the currentUser object in the session variable (even though the currentUser object is not null). However the password property in the currentUser object is null.
View 3 Replies
Aug 30, 2010
I've scenario where I want to insert data into database without post back. there are around 12 to 13 fields which i need to insert. I'm passing DTO from the client side which is actually Json object. Now the problem which i'm facing is how to convert that Json object which i got in webservice to the "class" (in my case class name is User) object.
[Code]....
In the above case AddNewUser method takes the object of User class. But i'm getting casting error. So how do I convert Json object to the "User" class object?
View 3 Replies
Jul 20, 2010
I have an existing class for an input, is it possible to add an additional class for the object in C#.net, instead of doing a if/else and not having a preset class on the object in the first place?
View 3 Replies
Feb 19, 2010
I am declaring a list in my class, populating the list in page load and using the list in various methods in this class. But, I get this error at every instance where I use this list in the methods. Error: System.NullReferenceException: Object reference not set to an instance of an object.
public partial class ViewBG1 : HealthServicePage
View 3 Replies
May 28, 2010
I'm experimenting with validating forms in the asp.net MVC framework. I'm focusing on server side validation for the time being. I've come across an error that I'm not sure how to rectify. System.NullReferenceException: Object reference not set to an instance of an object. The code that throws the error is:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create([Bind(Exclude="ID")] MembersCreate mc )
{
mc.Modules = ModuleListDataContext.GetModuleList();
ViewData.Model = mc;
//Validation using ModelState
//
//
//line below errors when form field is empty
//
if ((string)mc.Member.Username.Trim() == "")
ModelState.AddModelError("Member.Username", "Username is required.");
if (!ModelState.IsValid)
return View();
try
{
// TODO: Add insert logic here
return RedirectToAction("Index","Home");
}
catch
{
return View();
}
}
When I put spaces in the field it performs exactly as i want, but if I leave the field blank and press submit I get the error. What's the best way to avoid this error and still validate blank form fields?
View 1 Replies
Apr 24, 2010
I have a registration form. Settings of this form, like which fields are required I get via webservice. So I need programatically validate this form. I decided to create variable count of requiered field validators in Submit click. The validator is created in external object that holds a field settings.
[Code]....
I tried to debug it and GetValidator() created RequiredFieldValidator, but in btnSubmitRegistration_Click after that, validator was null. Object lost it's reference. Where is the problem?
View 3 Replies
May 10, 2010
In asp I want to add row to my gridview when I read barcode. But when I want to add second row , gridview.datasource = null. So, my first row is removed from gridview in TxtBxBarcode_TextChanged event.
TxtBxBarcode and gridview are in the different update panels.
How can I prevent this "gridview.datasource is null when Postback" ?
View 4 Replies
Nov 18, 2010
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?
View 5 Replies
Jan 30, 2011
Actually i want to cast the type from find control to div but i cant find the class with div or body or form name why so?
View 5 Replies
Jan 12, 2011
I've been looking around and trying a lot of different tactics to solve this issue but basically the senario is this.I have a gridview with a fileUpload in it.I can upload a file perfectly and it writes to the database.The trouble starts when I update a different cell and don't touch the cell with the fileUpload in it,it'll postback a null value to the database.
How can I keep the fileUpload control from sending a null on postback to the database so it won't clear out my entry if there isn't a new one to replace it?Or alternatively,how to I default the value to the old value on postback if nothing was entered through the FileUPload control?
[Code]...
View 4 Replies
Jan 12, 2011
A common problem in repeater controls where you want to display data for update (like a list of user phone numbers that can be updated and submitted back to the database) is where to store the database unique row identifier. So, I created a custom Textbox control that I've added a Data property to. I populate this data property with the unique row id. The problem is that when I post back the list and go through the repeater items the control's data property is null. The custom control looks like this:
[Code]....
The tag in the repeater looks like this:
[Code]....
I have a custom checkbox with the same data property and it works fine. I actually put in the same repeater with the textbox control and the checkbox control have the row id on postback but the textbox did not. Is there some limitation on the textbox control that might be causing this.
View 1 Replies
Apr 27, 2016
I want to change the class of an object dynamically in C#
Main Class : handleOperator objOpr = new handleOperator();
Then for object objOpr I need to access the methods for another class Class2 :
Means, I want objOpr = new Class2();
View 1 Replies
Jan 26, 2011
I bind textbox to a property of an object. After running the app, if the value of textbox is changed, I expect the object to update this property .This does not happen. I also understand that I am recreating the object from viewstate on postback, which is wrong. how to persist the state of object on postbacks all.
[Code]....
View 1 Replies
Jul 13, 2010
i have a list of contacts (generic list) and i bind a gridview to it, i get the list displayed on the griview that fine, now i'm trying to get a contact object when i click a button on the gridview (button is a template field) i want to get the object back from the generic list, not just an ID using data key names, even the index of it in the generic list will do.
View 6 Replies
May 14, 2012
How to create object of class file (asp.net) using javascript and call is methods.
View 1 Replies
May 27, 2012
I am trying to develop logic to add dynamic controls to page via class method. So I want to know how can we access the ASP.Net Page object reference in class method.
View 1 Replies
