I have several divs in a nested gridview which are bound to att runtime with the command div id="div<%# Eval("id") %>". I then set the visibilty of the div via javascript. The problem is that the visibilty setting isnt retained between postbacks. (Im using a filter feature that filters the rows in the nested gridview).
How can I retain the visibilty settings for all the divs created dynamically? (Could be up to fifty divs.)
If you are making the divs visible with javascript, when you postback they dont save their current state. However, you could make an ajax call to update the database with their current state each time you change the state with javascript.
If it is not meaningful to store the div's state in the DB: Store which divs have been set visible/invisible in a asp:hiddenfield. Then when the page reloads, reset the div's visible state.
Related
i am dynamically adding and removing a different user control from a to a place holders.
The user controls have lot of asp.net controls like cascading dropdowns with autopostback true.
The whole page is in a update panel.
After every postback i again add the control added previously and the which control is added previously is maintained in a view state.
The problem: Only first time the content in the textboxes get cleared after the first postback(caused by changing the dropdown)
Any help is appreciated
You need to make sure that your dynamic controls are being added in the Page_Init event in order for them to retain their data.
I am creating a program with asp.net c#, i am using multiple gridviews to show different criteria of data on 1 page, each of these criteria has a title,
Now, if one of the gridviews happens to have no data it will not show, however the title of the gridview will still be there as it is purely html fieldset and legend.
Are there any functions i could use to trigger the visibility of the title from the c# code?
Thanks
(screenshot below)
You can add runat="server" to fieldset and set Visible = true or false as usual (of course you need to set an ID, too).
You can surround each grid in an <asp:Panel... with a visibility on the panel set to a server based property (e.g. Visibility=<%# RecordsReturnedGreaterThanZero %>
so that the panel will only render the contents if there are some records returned in your query. Simply provide a property in your codebehind that acts as the boolean operator
This old chestnut again.
My page is constructed as follows; I have a dropdownlist which is databound on first load. When the user selects a value from this, a postback is performed which then databinds a repeater control.
The ItemTemplate of this repeater control contains a placeholder control. In code behind in the ItemDataBound event of the repeater, I am adding two controls dynamically to this placeholder, a hiddenfield and a checkbox.
When the user clicks the save button, I then want to iterate over all those dynamically created hiddenfields and checkboxes and determine their values. However when the user clicks the save button, those controls no longer exist as shown in the page trace.
I know this is a lifecycle issue and the articles I've seen on this suggest using Init methods to dynamically create your controls but I can't because of the way my page works, e.g. the repeater control only appears and binds after a value is chosen from the dropdownlist.
What do I need to do to maintain the dynamic controls through the postback caused by clicking on the save button?
The problem is when you hit the save button probabily you dont re-bind the repeater and the controls you have added at run time withint the ItemDataBound event are not longer available(because they don't exist anymore)
Why don't you add those control at design time using the Eval function the set up the value of the hidden field?
You just don't create them dynamically just on the on selection change of the drop-down set visibility true or false for the repeater that will solve your problem.on post back you have to again create those control as they are Dynamically created.
I am creating online booking page.
I got some example page you can see in this link
http://www.parkercorporate.co.uk/webbookercc/OneForm.asp
I need the same behaviour in my site whenever user selects value in pickup dropdown list in the right side I need to change the text values or view.
To do this behaviour how should I write code in ASP.NET and c#.
Thanks
Ranam
First, use an UpdatePanel so you don't see any visual postback.
Second, set the AutoPostBack property on your DropDownList to True.
Third, handle the DropDownList's SelectedIndexChanged event. This will now fire after every change in the DropDownList, because you enabled AutoPostBack.
In the event handler, you can now change the ActiveViewIndex of the MultiView, or show/hide controls, change textboxes, etc.
First, create different blocks (i.e divs) and give ID's to them.
Then, for each value in the dropbox, fill the divs w.r.t it.
Assign "OnChange" event to the dropdown, and in the handler, set visible or invisible to corresponding block.
On the other hand, If you want to do this on client side, I strongly suggest you to use JQuery, to prevent a lot of requests going to server.
Check this out with JQuery:
make visible div on dropdown select in jquery
If you won't fetch values from database, there is nothing complex about this page. Because it just writes hospital if you choose hospital etc. and changes control's visible state.
Even if you think you need db queries when dropdown's selected change event, actually at this page there is no need. Just store db values in hidden controls (like Hospital- for Hospital) and when dropdown selection changes, write hidden's value completely in javascript
I ran into a problem recently when using a repeater that I was adding dynamic controls into and although I've got a workaround that does functionally exactly what I want it to do, I'd like to know if there is a better way to do it for my understanding. I've been working with ASP.NET for about 6 months now, and everytime I think I've got the page lifecycle/viewstate completely sussed something crops up that I can't answer.
I was creating a form where users could register their interest for an event, and register for multiple people.
The aspx went something like:
<asp:Repeater ...>
<bunch of formatting and always there controls like firstname/lastname/address>
<asp:PlaceHolder ...>
<dynamic controls for workshop selection go here>
</asp:PlaceHolder>
</asp:Repeater>
An event can have workshops that the user can register for, and the availability of the workshops is dependant on the date that they choose to go to the event on. The availability of the workshops is dependent on the date, so they can't choose the workshops until they've selected a date.
Anyway the dynamic controls that I'm adding are basically a bunch of literals and a bunch of radio button groups.
I started off by adding the controls in the ItemDataBound event handler, but when saving my repeater items back to my delegate list the ViewState of the radio buttons was never updated. All the fields that were referenced in the ItemTemplate were handled fine, but not the radio buttons I was adding dynamically.
I tried to use the ItemCreated event instead, adding my buttons there, but that didn't seem to make any difference. In the end I settled on a workaround which was based off of this. Basically I'm just outputing the HTML input fields in a literal and reading them back from the request.
It all works perfectly now, and I'm happy with the functionality, it just seems really dirty to have to output the radio buttons as HTML inputs directly rather than use a server side control. Does anyone have a clue about why the ViewState wasn't being restored properly?
Just to be clear, the controls were recreated in the same order everytime, with the ID properly set. I'm using dynamic controls all over the place and they're working fine, I just can't get them to work in this case when I'm adding them inside a repeater.
//more clarification
I can't create these controls in Page.Init as the user selects the date which causes a postback and I have to wait for the viewstate of that control to load before I create the dynamic controls.
You're creating (or re-creating) the controls when the repeater is bound to its data source. If this happens after the ViewState has been loaded by the page, the ViewState won't be available to the dynamically-created controls.
Check you're binding your repeater early enough - Page.Init is OK; Page.Load is too late.
It is worth noting that Radiobuttons controls do not work 'out of the box' in repeater controls. Repeater controls inherit the INamingContainer interface which ensures all rendered html controls have unique name attributes. As radio buttons use the name attribute to group themselves this means you will not be able to create groups of radio buttons i.e. setting the GroupName property will not have the desired effect as the Repeater will override this and create unique names for each RadioButton.