Databinding - How To Delete An Item In .NET Listview And Persist The Datasource
Apr 27, 2010
I have a collection of objects I bind to a Listview like this:
if (!IsPostBack)
{
List<Equipment> persons = new List<Equipment>
{new Equipment{ItemName = "Sworn", ItemCount = 7, ItemCost = 255}, [code]....
I want to Add/update/delete from this object collection and submit the final data object collection to the BL when the user saves... Rather than just delete/add/update everytime a row is changed.So my question is how do I maintain state for that datasource? I have tried this (delete example)
But it does nothing. I can't rebind it to the datasrouce because at this point the datasource is null.. I assume the listview keeps its own view state which contains the data?... I guess worse case I can always hold the Object Collection in a Session object.. ..
I need you assistance, Dynamic Delete LinkButton with CommandName=Delete gives me an error: Delete can only be called on a valid data item. nfact I am designing a Complex Grid using .Net 3.5 ListView Control with Scrollbar and Fixed Toolbar: This grid consist of 3 Tables:
1- footer 2- Toolbar Control 3- Scrolling Data Grid with Header
ListView give us only one ItemPlaceHolder to Bind Data as per LayoutTemplate, so I cannot able to manupulate my Toolbar Controls with ItemTemplate :(, therefore I decide to use ItemDataBound to add ImageButtons Dynamically using Init Page Event and I am able to get the result as you saw above:
ImageButton with funnel icon is with CommandName="Filter" ImageButton with magnifier icon is with CommandName="View" ImageButton with stop icon is with CommandName="Delete"
Now I can able to handle Filter and View with OnItemCommand Event but when I click Delete button I am getting an error as shown below: The grid used CSS I am sending you the HTML and code behind to resolved this problem: HTML CODE:
I've a listview in which i'm binding data from objectdata source. I have a requirement where i've to allow edit/delete for only certail listviewitem which meets specific requirement. How do i dynamically set that some item can be only be edited not deleted thus only edit button/link should appear and vice-versa.
First time using a ListView control, I have it inside an UpdatePanel:
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When the UpdatePanel Loads, it feeds the data to the ListView. Whenever the user clicks on a row in the ListView, a new window displaying a "note" pops up, the ItemDataBound event ties it all together. What I'm trying to do is add a button to each row so that the user can delete the row. This would call a Sql statement and then the row should disappear. I followed a couple of articles I found on ListView on how to do this, so I added a button called imgBtnDeleteNote (see markup above) and set the CommandName = "Delete", hoping that it would trigger the ItemCommand and ItemDeleting event (I have some bogus code in them, first I wanted to see if they would trigger).
The problem is that they don't seem to get triggered when I click on the delete button. All the rows in the listview disappear, and when I manually refresh the page they come back. My guess is that the events are not firing because I'm not using a DataSource object in the aspx code, but I'm not sure.
I have dropdownlist which items are generated using SQLDataSource. And there is a "Delete Button" next to it. When user selects item from dropdownlist and presses that button I want the item to be removed from DB. Here is the question "How can I achieve this using sqldatasource Delete Command?" I do can remove Item From Code Behind. But i believe it's more efficient to use sqldatasource delete command.
I know the question has already been posted here but we didn't get to an real solution.I have bound my ListView to an SqlDataSource and I want to write some text in a control present in the view created in the LayoutTemplate depending on some properties of the rows returned.Obviously, I'm using the ItemDataBound event to feed my items but this is not the point.
The spontaneous solution was to bind the ListView.DataBound event and access the raw datasource (a DataTable?) and do the required calculations.I inspected the Items property and, despite it was not empty, the related DataItem property was null.The only work-around I can come to is to execute the calculations in the ItemDataBound event and accumulate the result in some private fields. But it's really ugly to see and makes harder to get some of the required values.
I created a ListView and attempted to delete a record using the delete button and native procedures. It failed and threw an error.Pass in a valid dictionary for delete or change your mode to OverwriteChangesIn researching this issue, it appeared there is a problem with the list view when deleteing and ConflictDetection is set to
Basically when editing an item, I want to bind its ProviderId value to the DropDownList's select value.DropDownList is getting its list of values from other entity entity_List as you can see.
I have a listview set up in "flow" mode where the existing records are all on an extended page so you can scroll down to any record.
The InsertItem Template is in the first position, making it easy to insert a new record.
And one can scroll down the page to any record, click the edit button and update that record -- nice having everything on one scrollable page.
I am running into a problem with validations. I have validation controls restricting inputs for all the textboxes on the Insert Item template. They work fine. And on Item Inserted I am running a page validation:
Page.Validate() If Not Page.IsValid Then e.Cancel = True End If
which works fine also.
The problem occurs when I scroll down to an existing record, and go to edit it. I have all the same validation constraints on the textboxes for the EditItemTemplate as I have on the InsertItemTemplate. But I cannot successfully do a page validation on updating the record. The code I am using on update is:
Protected Sub LVRentals_ItemUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewUpdateEventArgs) Handles LVRentals.ItemUpdating Page.Validate() If Not Page.IsValid Then e.Cancel = True End If End Sub
This results in a Cancel even if there are no validation errors on the InsertItemTemplate because the Page.Validate() seems to be causing the InsertItemTemplate to think its fields should be filled out also.
Here is the code for a typical entry of the InsertItem Template:
[code]....
All the controls in the Edit Item template are part of ValidationGroup "edit1" and those of the InsertItem Template are part of ValidationGroup "edit2"
How can I get around receiving validation errors on the InsertItem Template when I am trying to validate just the EditItemTemplate when both are present on the page?
I am using list view to display the the data but i am getting an error like An item placeholder must be specified on ListView 'ListView1'. Specify an item placeholder by setting a control's ID property to "itemPlaceholder". The item placeholder control must also specify runat="server.Even i have specified the itemplaceholder id but no use still same error.
I have triple-nested ListView controls on my asp.net page, each nested within another. I use the OnItemDataBound event in the 1st ListView to set the DataSource of the 2nd level ListView. The 3rd ListView is contained in the of the 2nd ListView. I want to assign the same DataSource to both the 2nd and 3rd level ListView datasource controls, but I cannot figure out how to access the 3rd level ListView in order to do that.
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The level1_ItemDataBound method finds the level2 control, casts it as a ListView, sets its DataSource and executes the DataBind. At this point I'm stuck trying to get Level3.DataSource to be set to the same as Level2.DataSource.
I am going to outline my setup then where i am failing
UpdatePanel1 - Contents : 3 textboxes and AddButton UpdatePanel2 - Contents : 1 GridView and SubmitButton
AddButton adds new row to DataTable with data from textboxes, binds DataTable to GridView SubmitButton sends data to database. The Adding of a row works to add the row to the gridview, but it won't add a second or third and so on, only adds the 1. SubmitButton belives the DataTable that GridView is databound to is null and won't send anything to the database. How can i get the datatable to persist between the two update panels? Do i use Sessions as my storage location? Page
I am trying to populate the ListView using LinqDataSource data source but the issue I am having is.I need to load the listview on Search button click action.
IN the page_load I kept like this: =========================================== LinqDS.Selecting += new EventHandler<LinqDataSourceSelectEventArgs>(LinqDS_Selecting);
protected void LinqDS_Selecting(object sender, LinqDataSourceSelectEventArgs e) { e.Result = ObjectDS; } ============================================= This works fine but this happens on page load,i want this binding to happen on button click?is there a way to do this?
I've created an asp:ListView and attached it to an asp:XmlDataSource. I would like to support the delete command for my list, so I've added the following button:
somewhere on the net I found very useful example of programatically databainding the treeview control (code blow). I use this treeview as menu bar in my masterpage. It works fine but with one exception: when I click the node of this treeview I'm redirected to the correct page but after page is reloaded my treeview is collapsed and node I chose just before is not highlighted. What to do to correct this problem. Do you know better examples of programatically databainding of the treeview control? Maybe it will be better to bind data to the sitemapdatasource and next to the treeview. Then I shouldn't have to worried about this?
I have one datalist,in datalist one column is UserName and in second column one button i.e. Delete. When I click on Delete then delete the this row from datalist.how to create this functionality.
I am trying to display checkboxes in front of every row in list view. So that after selecting the desired checkboxes user clicks on delete button and we should delete that records.
I have a DataList containing a list of elements(ASP.Net app). To delete an item i first used tha classic javascript confirmation. As i found it ugly,i want to use a confirmation box plugin. when i click OK==>Delete the item from DB(using a webservice) But how can i update the DataList. The situation is liek: when u add a comment in Facebook. delete link==>Conf box==>Delete==>Comments List update.
I added a Gridview to my page and added a new item a delete button, now when i push that button there is an error... Do I need to add some code for it? And yes, can you give an example?
I keep getting Object Reference not set to an instance of an object errors when I try to use the ListView delete function. It is a fairly freshly created listview and is very close to the original template so not sure what is going wrong. Some possibly relevant code:
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I also put in a breakpoint in the deleting event (only reason I added the deleting event) to look at the status of everything. When I do: Contact delContact = (Contact)e.Entity; and look at the values, the values for almost everything are set to null. It does have the correct value for the ID of the contact object that needs to be deleted. When I continue to step, it jumps to my designer.cs file and appears to break here:
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likely because _Case_ID is null. The exact exception I'm encountering is: System.NullReferenceException: Object reference not set to an instance of an object. While I could probably re populate the object with correct values, that doesn't seem likely to address the real cause of the problem.
