How do I force a CascadingDropDown to refresh it's data without a page refresh? I have a button on the page which adds a variable to the Session which is then used to set the selected value of all the drop downs. However I can't seem to force the refresh of a DropDownList without a full refresh of the page.
Let's see - the button on your page probably has an event associated with it to respond to it being clicked, right?
Can't you just reload and re-assign the data to the dropdown in the button OnClick event?
public void OnButtonClick(.....)
{
.....
CascadingDropDown.DataSource = .......;
CascadingDropDown.DataBind();
}
Or am I missing something?
Related
I am using AjaxToolJit Tab Container and the problem is when i refreshes the page the default tab is set to 0 but i was in 4th tab when i refreshed the page.
AutoPostBack=true
help me for a while but when i used UpdatePanel in the same page causes the same problem again.
If you need to keep selected tab index across full post back or page refreshing with F5 button then you must save selected tab index in session on SelectedIndexChanged event and then use this saved index value in Page_Load event handler
The situation:
I have user controls with buttons that have hooked events. Controls with events need to be initialized in Page_Load or earlier.
I wish to spawn these user controls dynamically by clicking an Add button.
It is important to remember that events, such as click events, are not fired until just before Page_LoadComplete.
Broken Solution A:
Page_Load: Dynamically create an Add button, hook click event.
User clicks on the Add button, triggers postback.
Page_Load: Creates the Add button as usual, and hooks click event.
Page_Load: Doesn't know that the Add button has been clicked yet, so it doesn't know to spawn the user control!
AddButton_Click: Page finally aware that a new user control should be added upon the next Page_Load.
User cannot see the control they added, because another Page_Load has been triggered.
User reloads the page by clicking a button, refreshing the page, etc.
Page_Load: Creates Add button, and hooks click event. Now aware of added user control, creates user control. Hooks events within the user control.
User clicks on button within user control, triggers just fine.
Result: User has clicked to Add a new user control, the server is aware that the control should exist, but the user does not see it until they trigger the page to load again (by clicking another button, or refreshing, etc).
Naturally, I took a look at the life-cycle, and see that Page_LoadComplete occurs after events, so if I place any event-dependent code in Page_LoadComplete, all should be well?
Broken Solution B:
Page_LoadComplete: Dynamically create an Add button, hook click event.
User clicks on the Add button, triggers postback.
Page_LoadComplete: Creates the Add button as usual, and hooks click event.
AddButton_Click: Page aware that a new user control should be added upon the next Page_LoadComplete.
Page_LoadComplete: Aware of the button click, dynamically adds the control, with its own internal button click event.
User clicks on button within the added user control, but it does not trigger!!
Result: Everything works great, except the button within the added user control is inert.
The conundrum is: I need controls to spawned by a button click, which means I need to put my Controls.Add(...) code in Page_LoadComplete. Inversely, I need the controls being added to have working events, which means the Controls.Add(...) code need to be in Page_Load. I have a perfect dichotomy.
The only janky solution I can think of is taking solution A and forcing the page to reload manually after clicking the Add button, which is a waste of bandwidth and processing.
This might not be the best practice, but you can check Request.Form for the evidence of add button click during the Page_Init event and add the controls there. It should solve your problem.
I have a page (page1) with a LinkButton that, when clicked, will take the browser to a new page (page2).
When I click the LinkButton page1 posts back and hits the Init and Load event handlers for page1, and then moves on to page2.
How can I tell in the page1 postback that I am about to be taken to a new page, as opposed to clicking a Button that causes the page posts back but does not navigate away?
You can also add OnClick events to your code behind for each button, and in the case of the one that is to postback to another page, do a Response.Redirect. The limitation of that however is that if you need form data on "page2", you will lose posted form data on a Response.Redirect.
It appears that you're not using the OnCLick event of the LinkButton, If you use the event, perform the action of the click there, not on the Page Load event?
I have a user control that has several buttons.
On page_load, I want to run a method unless a specific button was pressed.
When I check the sender on page_load inside the user control, I just get the name of the user control and not the button itself.
Is there a way that I can determine what button was pressed on page_load? Otherwise I will have to come up with some hacky method to solve the issue.
I think you can check Request.Form ("__EVENTTARGET") - that should contain the ClientID of your control.
This refers to the value of a hidden field the ASP.NET event handling framework uses to keep track of what the user clicked. When the user triggers a post-back, some JavaScript on the page sets this hidden field to the ClientID of the control you clicked before submitting the form.
Can you create a property in your user control to return the clicked button (or set a flag or whatever), an set it in each button's click event inside the user control?
Are you sure you're handling the page model correctly? The Page Load event happens (to build the server side object model), then your control is going to handle the button click event bound to the control.
Page Load can come for any number of postback reasons besides buttons in your user control being clicked.
What about buttons in other controls on the page?
There's sometimes good reasons to do this, but I also I worry that you're just hacking around the ASP.NET page model.
Here's a simple way to check if a specific button was pressed:
protected bool isButtonClicked(string buttonName)
{
bool isClicked = false;
foreach (string ctl in this.Request.Form)
{
if (ctl.EndsWith(buttonName))
{
isButtonClicked = true;
break;
}
}
return isClicked;
}
I have an gridview that I am adding onclick events to a checkbox column via:
cb.InputAttributes.Add("onclick", "checkClick()");
everything works fine, but when the user clicks the save button on the form, (which is within the updatepanel), suddenly the onclick event of the checkboxes stops firing!
Is this a problem with the ASP.NET AJAX?
The weird thing is that I am seeing the onclick event on the source, it just doesn't fire.
Help!
The source will show you the state of the document when first received from the server, not the current state of the DOM. What is likely happening is the update panel content is being replaced by new HTML content. The elements to which the original click events were bound are no longer in the dom.
The onclick events will need to re-bound to wire-up to the new elements that have arrived.