Web Forms :: How To Read Object Data From ListBox
Oct 11, 2010I've already binded object data to ListBox, like..
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how can i read this object data.
I've already binded object data to ListBox, like..
[Code]....
how can i read this object data.
how I can read the selected field from the listbox?I have MSAccess table attached to the app.I can get to the properties, but I don't know which property gets me the data of the specific field.In VB it would be "listbox1.Column(x)", where 'x' represents the column number in the listbox1.I am using Microsoft Visual Web Developer 2010 Express
View 2 RepliesI have just recently converted my VB code to C# and now having this error when I try to add an item to my listbox, and the value is coming from the item page. I get the error at this segement:
lstboxCart.Items.Add(cartItem.Display());
My listbox is supposed to add the product's name, quantity, and price onto one row.
Here's what I have so far:
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My guess is that the source of the problem could be in the foreach loop from my cart class, shouldn't I be using that for arrays only? If I need to post any markup code or any other class, let me know.
I have a website written in C# that was running fine on one server. We moved it to another server and have a couple issues. I am mainly a VB.NET coder but can do a few things in C#. This is not a project - it is a website and can open it in VS2008 no problem. This is an admin site for the whole website where the user can add customer comments, etc. When logging in, it works fine. I can go to one of the admin pages after logging in and works. If I go to two other different pages, I get this error:
Object reference not set to an instance of an object.
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It turns out this is in the main.master page and it is used by the other pages that load fine. The ApplicationTitle variable is set right in the web.config file and like I said, it shows on the other pages.
My question is why would this code work fine for some pages and not two others? All of these admin pages are under a folder called Admin and the web.config file is in the root folder of the website. Its almost like these two pages cannot see the web.config file in the root folder? Why would that be if thats the case?
I have an object datasource which is using Business object as a myconnection
The method i have defined under myconnection is
Publicstatic
DataTable getfn(String dtype,
String did,
String dprefix,
String dname)
{
datable table = new datatable(); then declared stored proceedure and defined parameters and assighned values
In the stored proceedure it has a query like select column1,coloumn2,coloumn3 As Call from table where
I need to take data from Call and display it to the gridview through object datasource .
I am designing a program that will let me enter the name of an item to swap and adds the swap to an array list when a button Add is pressed. Once the item is added to the array list a Sub Procedure should be called which displays the contents of the array list in a list box.
The system will also allow me to remove items from the array list using a Remove button
followed by updating array list.
I have done some part which puts item into the listbox1 which i named lstSwapList.I would need some assistance on the Sub Procedure to display the Value or Description on the other listbox2 which i have also named lstContent,if a value is selected from the listbox1.
I would also want to know how to update the Listbox content,However i hv added a sample of the way i guess it may be.
Any complete solution from anybody on the Sub Procedure and the Update Swap procedure will be greately appreciated.
The script below is what i have done so far.
Partial Class _Default
Inherits System.Web.UI.Page
Protected Sub lstContent_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstContent.SelectedIndexChanged
End Sub
Protected Sub lstSwapList_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstSwapList.SelectedIndexChanged
End Sub
Protected Sub btnAddSwap_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddSwap.Click
Dim SwapValue As String = "Sixty Pounds"
Dim Counter As Integer = 8
Dim SwapN0 As Integer
lstSwapList.Items.Add(SwapValue)
lstSwapList.Items.Add(Counter)
lstSwapList.Items.Add(New ListItem("300", "1"))
lstSwapList.Items.Add(New ListItem("ASP.Net", "2"))
lstSwapList.Items.Add(New ListItem("Programming", "3"))
SwapN0 = lstSwapList.SelectedValue
For Counter = 0 To -1
SwapN0 = lstContent.Items.Count
Next
End Sub
Protected Sub btnDeleteSwap_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDeleteSwap.Click
lstSwapList.Items.Remove(lstSwapList.SelectedValue)
End Sub
Protected Sub btnUpdateSwap_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpdateSwap.Click
End Sub
End Class
=======================================
Sub UpdateSwap(ByVal valueA As String, ByVal ValueBAs String, ByVal ValueC As Integer, ByVal ValueD As Date)
I want to cast back my ListBox Item into my Business Object. Following is the code. ListBox Populate Code on Page Load...
if (!Page.IsPostBack)
{
SalesDBEntities ctx = new SalesDBEntities();
this.ListBox1.DataSource = ctx.SalesHistories;
this.ListBox1.DataTextField = "Product";
this.ListBox1.DataValueField = "SaleID";
this.ListBox1.DataBind();
}
And here is
protected void ListBox1_SelectedIndexChanged(object sender, EventArgs e)
{
SalesHistory sh = new SalesHistory();
//sh = (SalesHistory)ListBox1.SelectedValue; Error Here. How it is possible
TextBox1.Text = ListBox1.SelectedValue.ToString();
}
There have an error "Object Reference not set to an instance of an object" when using objusername.intuserid=listbox1.selecteditem.value.
View 1 Replies have an issue with a list box. I populate the list box using :
listbox1.datasource = myCollectionOfCars
listbox1.databind()
When i go to retrieve the selected item from the listbox using
Car myCar = (Car)listbox1.selecteditem;
an error is generated
cannot cast expression type system.web.ui.webcontrols.listitem to type car
i have read several tutorials and many of them use the above code.
I'm creating a custom module and I need to be able to read the html output that's written to the HttpResponse object. Can anyone provide direction on this?
View 2 RepliesFirst of all, here comes the load part.
Structure MainStruct
Dim Ans1 As String
Dim Ans2 As String
End Structure [code]....
The question is how can i read back the contents of the list, stored in the Session?
I mean something like...Build = Session("MyData")
I have two list boxes, one has a list of available users (about 1500 items) and the other is blank. There is a button to add the seleted items from the first list box to the second one. Both of these listboxes are within an update panel and for some reason it takes over 20 seconds for the items to show up in the second listbox.
Is this normal? Is there an alternate, faster way of doing this?
i when i m set some value in data object. and create new object in form then new object contain previus value in it.
View 2 Repliescan you please help me to brainstorm the possible causes of this error. I've got a paged repeater with localisation bound programitcally to an sqldatasource using a stored proc. I can post code if needs be but it's rather long. I'm looking for typical causes of this error + will make note for future reference!
erver Error in '/WebSite4' 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.
Source Error:
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Line 233:Line 234: Repeater1.DataSource = PagedResultsLine 235: Repeater1.DataBind()Line 236: doPaging()Line 237: End Sub
I am trying to get the value of the id field in my gridview but I keep coming up with this error when i do selectedValue or selecteIndex
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
How do I get that id? What I am trying to do is when the user select that link it will delete that information from the database. Here's my code:
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I have a nested gridview
i get error:Object reference not set to an instance of an object
when i try to get the text in the footer template of the inner gridview when clicking on the linkbutton!!!
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Again, I am new to the ASP.NET world, and I come from a Windows Forms background. I'm working with an ObjectDataSource that retrieves a collection of business objects. With the collection, I am going to be binding it to a CheckBoxList and other various controls. The business object that I am using is an Employee.
To get all of the employees, I create an ObjectDataSource and set the "Select" method. I then set the DataSourceID of the CheckBoxList to be that of the ObjectDataSource. When I load the page for the first time, I see all of the employees. Now, the user goes through this page and selects all the employees they want to see information about (by checking the box next to the employee name). Finally, the user hits the button called "Display." Upon postback how do I get a list of those employees? I've tried the following solution, but I'm not sure if it's the best practice in obtaining all those employees again. Here's my solution...
In the CheckBoxList, I set the DataTextField to the Employee's name. I also set the CheckBoxList's DataValueField. This property is a little different. I set this to be a UNIQUE IDENTIFIER, which can distinguish this employee from other employees. Now, when the user hits the button "Display" I use my ObjectDataSource again and MANUALLY call ObjectDataSource.Select(). I cast the returned value as a List<Employee>. Finally, I iterate through all list items in the CheckBoxList...
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If the item is selected, I parse through my list of employees that was returned from the bjectDataSource.Select(). I use the item.Value and compare it to each employee's "key." If the key is found, I know that the employee is selected. I put this employee in another list called EmployeesSelected.
Finally, I take EmployeesSelected (which is a List) and set my GridView's .DataSource and call .DataBind() on the GridView.
Is this the "best practice" of re-obtaining the Employees that are selected on my page, or am I making this too complicated?
I am using C# and VS 2008 attached with access database, where Date1 is the PKey in Text defined.
I am getting the above error when i am trying to insert it into the access database.
here is my code
aspx :
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Code Behind :
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My problem is I get an "Object reference not set to an instance of an object." error at runtime on the line "ddl2.SelectedValue = cat1". Ironically I got this from an example on the internet and the only difference is my Cat1 varible which has the correct value at runtime.
<asp:FormView
id="frmCustomer"
DataSourceID="srcCustomer"[code]....
I would like to enable/disable the field BagNo in my gridview, depending on the value of another field in the gridview called ScriptNo, when I click the edit button I get this message "Object reference not set to an instance of an object".
here is the code
Protected Sub GridView1_RowEditing(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewEditEventArgs) Handles GridView1.RowEditing
Dim row As GridViewRow = GridView1.Rows(e.NewEditIndex)
If DirectCast(row.FindControl("ScriptType"), TextBox).Text = "TTA" Then
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I tried to get the heade row text with the following code, but it failed.
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Error returned was "Object reference not set to an instance of an object." on this line:
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The stored proc fired to populate my grid view gets a column CasNo.The GridView has a DataBound item for CaseNo.
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Then Why does this get null value: string caseNo = dataRow["CaseNo"] as string;
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why I get this error:
Object reference not set to an instance of an object.
when I try to access a LinkButton inside a Repeater as follows:
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I need to change the row.forecolor = drawing.color.red.
in my gridview i have a STATUS field, its ItemTemplate is LABEL1 and its EditTemplate is DropDownList1.
on loading I have successfully changed the forecolor, but when I edit it gave me an error:
Object reference not set to an instance of an object.
I get the error:
Object reference not set to an instance of an object