I have a form that contains a TextBox. A pop up window will return a value and put it into the TextBox. when this happens, I need to populate another control. I tried tried "onChange" but it was not triggered . How can this be achieved?
You can use onchange, but this usually won't wire until the box loses focus. There's also onkeyup, which you want to use if you want the new text immediately.
Can you control the window populating the textbox? If so that's your best route, since it's the source of the event, just invoking the third control population from there, via a function in the parent page.
If there are no number based effects, you can bind the event to onchange, onclick and onkeyup to handle all cases, it'll run a bit extra, but if it's a lightweight operation, no multi-run side-effects and you want to cover your bases, it's a viable option.
Related
My problem is this: I need to have a way to repeat a custom textbox control with validators and have each validator fire for each control uniquely (as opposed to one text box failing validation and the validators fire for all other controls also using that validator).
My idea was maybe to set the control to validate property uniquely for the full client ID of each?
I've associated a custom javascript function to the text box blur. It uses jquery to nab the validator controls nearest to the sender (and only those nearest). I loop through them and call ValidatorValidate.
In addition to my above problem, this also allows me to only show the validation error that makes sense at the time (i.e. on blur of text box i don't want to show required field immediately because it's truly not required till i take action elsewhere... so I determine this by the sender and hook into this method in other locations).
I also don't show multiple. If its beyond my range specified, i only show that (as opposed to other custom validators i have that would otherwise fire).
Problem: Content Page with Wizard Control with UpdatePanel and Placeholder. Above the UpdatePanel is a DropDownList. I need to display different input controls below the drop-down list when the user changes the selection in the drop-down list. When the user clicks 'Next' on the wizard control, I need to be able to get the data out of those dynamic controls as well.
I know all the dynamic controls have to be created in the OnInit method in order to get the data back from those controls during the postback. However, when the drop-down list's SelectedIndexChanged event is fired, the OnInit method is called... then the PageLoad... and finally the handler for the SelectedIndexChanged event is called. ViewState hasn't been restored until well after the OnInit & PageLoad methods have been called, so there is no way to know what the user chose in the list box at the time OnInit is called... which exactly when I'm required to create the dynamic controls.
So... how do you solve this problem? Do you just have to write the entire page, or most of it, using JavaScript?
Thanks in advance.
I tend to use an old school method for this type of requirement. I would write all of the controls that are needed in the update panel, with their Visible property set to false. Then, on post back read the drop down's state and set the approperate controls Visible property to true. This way there is no "dynamic" controls, and due to the fact that controls whose Visible property is false are not rendered, they are not downloaded until the user should see them.
you can also use an asp:hiddenfield and set the value to a case var you mentally create. then run a small jQuery script on top to look at
$(document).on("change", "#ddlSelector", setControls);
then just make a function, for instance:
function setControls(event) {
event.preventDefault();
var selector = hiddenfield.val();
}
then any item to show/hide can be done with getting the tag:
$("#elementName").css("display", "inline");
or display, none to hide.
I used this at work because at times you need to change without firing the postback, but still collect data when they engage the form.
I typically avoid jQuery for many events for strength of code and security, but DOM element manipulation can be much easier at times with jQuery.
I would like to perform a postback when the droplistlist selected value changes, but only if it was changed via expanding the downdown and clicking an option, not is the user tabs to the control and uses the arrow keys. The reason for this is simple, keyboard accessibility.
Postbacks are triggered using __doPostBack('uniqueidofcontrol', 'commandname'); so when the list changes value (I believe in onchange event), it posts to the server. You would need to not set autopostback. What you would need to do is tap into the click event (if there is one) and then call __doPostBack(..) method upon that event.
HTH.
This is what I'm doing: Using jquery, I'm popping up a "form" over the page that lets the user search for branches of the company and select the one they want. When the form pops up, they can type in a textbox, and it will do AJAX requests back to the server to return the top n results for what they've entered, and those results will be put into a list for them. I want the user to be able to select one by clicking a link that says "select" or something, and at that point I want it to do a PostBack have the Branch Selector control that this is in change it's SelectedBranch property to the newly selected branch. I've got this all working right now with a hard coded list of LinkButtons, but how do I do the same thing with a dynamic list of links inserted with jquery?
Look at the HTML that gets emitted for your hard coded LinkButtons. You'll see that each one calls the JavaScript __doPostBack function when clicked. I believe this function takes two arguments: a control ID and an extra command argument you can use for your own purposes.
I would suggest adding a single control to the page whose only job is handling events for the dynamic links. Then, when you are creating the links with jquery, make each one call __doPostBack, passing the event handling control's ID for the first argument and some other string for the second argument that identifies which link was clicked. In the Click event for the handling control, look at the second argument value and do what you need to do.
The short answer is... you don't.
ASP.NET relies on the Viewstate for the current state of the controls, including items in a DropDownList or similar control. Dynamically updating a list on the client will not modify the viewstate, so will not be available on the back end.
The general workaround for this is to just add a hidden field which updates/stores the current selection via js on the client side. Then read it from this field on the backend rather than List.SelectedValue.
I have a GridView that lists a bunch of items and one of the columns has a link that displays a modal (AjaxToolkit ModalPopupExtender). Let's call that link "Show". In that modal, I have a asp:button for saving the data entered in that modal. Let's call that button "Save"
So when the user clicks on a "Show" link in a certain row, I'd like write some javascript that sets something in the "Save" button, so that in my code-behind, I can handle "Save".Command and use the CommandEventArgs parameter to get the value.
Is this possible, or do I just need to use a hidden input tag and set its value?
Not a direct answer to your question, but another possible way of solving the problem:
Place a HiddenField control on the page. In your code-behind, before displaying the modal popup, set the value of that control to the ID of the row that was clicked (or the row number, or some identifying value). Then in the code-behind of your Save button, you can just read the value of the HiddenField.
Well, after continuing the research, it looks like it cannot be done. The CommandArgument property might reside in the ViewState, but for this case, it is completely server side and cannot be changed using javascript.
If you are using Updatepanel, you need to place the Hiddenfield inside the Updatepanel. Otherwise you will not be able to get/set the value stored in hiddenfield.