In an ASP.NET webform, I have 3 TextBoxes, each linked to a different SQL Database Table. Now I want to store data into table when Textbox Change event occurs. I can do successfully with make Update Query in TextBoxChanged event. Now What I want is when this update operation going on I dont want it to make interrupt my page and other operations I want to perform. I use an Asynchronous Postback from the TextBoxChanged event.
The problem that I am having with this is:
When I change one TextBox and click on another TextBox, and hit "backspace" inside that textbox, the page reacts as if it was a browser back button-click, and redirect to other page.
I hope you can understand the question I want to perform TextBoxChanged and handle the asynchronous postback without interrupting other operations.
You will have to use jQuery for the capturing of the textbox changing. However, you cannot connect directly to onchange as the changed value is not stored until after the event. You could probably tie to the blur event if you only want to capture when the user changes and leaves the textbox, though. Otherwise, you will have to use a timeout to continuously check if the value has changed ( How to detect a textbox's content has changed )
Within that event, you should use AJAX to make the save calls for persisting the value.
Related
I have a lot of textboxes with the TextChanged event. There is also a master textbox at the top, which if I change it and press a "Change All" button, it changes the entire page of textboxes.
Now, the button exists almost entirely on the client side (just uses jquery to change the textboxes), but I want to know if it has been pressed BEFORE my program runs through the 100+ TextChanged events.
I tried adding a server function for it to set a boolean to true, hoping it would fire first, however, the TextChanged events fire first.
TL;DR I need to tell my program in which order to go through the events after a postback.
You really can't change the order of events in the ASP.NET page lifecycle...but you might still be able to accomplish what you're needing. Here's a suggestion...take it FWIW...
On the client side, you could add a Javascript event handler (or amend one that already exists) to populate a server-side form field with a magic value (doesn't really matter what). On the postback, inside the Page_Load (and/or in the TextChanged event handlers), check for the presence of the value when IsPostback = true. You might have to wire up (a bunch) of different handlers to make the same check, so this may be too cumbersome, but its at least the seed of an idea, perhaps.
Won't promise its very elegant, but it should at least get you closer to what you need.
In my ASP.Net web application, there is a textbox to receive ProductId. When the user enters data into the ProductId textbox and moves to the next textbox, I want to validate the data against a table and if matching record is found, I want to display Product details in different controls (readonly and normal textboxes) else I want to display a message about "New Product" and continue. I do not want to do the verification AFTER the user enters all data and press the Save button, but it should be done immediately. I was hoping that the Web Form textbox would have a LostFocus event, but do not know how to handle the requirement.
ASP.NET Validators don't have an ajax style immediate check.
Attach a custom validator to your textbox that hooks up to a validation method server side.
Using javascript, you'll need to hook up an eventhandler to the focusout event and make an ajax call. That call will send the value back to the server and get a response of valid or not.
This site : http://brian.dobberteen.com/code/jquery_ajax_custom_validator/ will help you with a lot of it, but one thing is this will fire only when the page is submitted. You'll want to hook up an additional event handler to your textbox to call the validation method on focusout
It's easy solution, read this article:
http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.customvalidator.servervalidate.aspx
You just need to preform javascript call to trigger server validation, use event onlostfocus.
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 have a textbox in one grid-view column where upon entering a particular value and losing focus of the textbox, should post to the server to get the text validated through a server-side method. If the entry is valid, a result set to fill rest of row cells would be returned, else the bgcolor of the textbox needs to be changed to Red.
I tried posting back through the obvious way, i.e. making the textbox's autopostback as true and wiring up a server-side OnTextChanged event handler to validate the entered value.
It is working with this setup, but is also affecting the remaining page controls behaviour. For example, if I click a button in some other grid after entering some text in the textbox, the OnTextChanged handler gets called thus preventing the button's click event, which I also wish to call to execute its functionality.
Kindly suggest what alternatives/corrections I should carry out to enable textbox content server-side validation plus making the other controls/updatepanels work as expected.
Me dumb. I tried everything from creating PageMethods, UpdatePanels to jQuery as hinted in lincolnk's reply. But the thing which finally worked was removing the Autopostback attribute from the textbox control.
After removing it the OnTextChanged event executed each time any server postback was initiated after changing the text. Thereby, executing both the OnTextChanged method and the other control's method. :)
I can think of a couple general approaches.
Create a web service with your validation routine and manually make the call (jQuery or whatever) when the text changes. Manually update the client display when you get a result.
Convert your gridview column to a templated field. Add a CustomValidator and wrap the textbox and validator in an UpdatePanel. Set the textbox to auto-postback and the UpdatePanel to conditional update so only the one you are using is refreshed.
Option 1 is kind of an end-around the typical asp.net process, and you would still want to validate everything on the server-side when the page is posted back.
Option 2 might have performance issues, since you're hitting the page again every time you do a validation.
I have a data access layer, a business logic layer and a presentation layer (ie. the pages themselves).
I handle the OnPreInit event and populate collections required for the page. All the data comes from an SQL server database and I do not use caching.
I handle a button click event to grab values from a form and insert a new object into the database. The problem is that by the time I handle the click event, the collections have already been populated, so the new item which has been inserted into the database has not been retrieved.
What is the accepted solution to this?
I could insert the new object directly into the collection and re-bind the GridView, but the SQL query selects only a set of objects and the new object could fall outside of this set.
Thanks!
I generally do databinding in two places in my pages:
Inside Page_Load, if !IsPostBack to load the initial state.
As one of the last lines in event handlers to show the result of adding/editing/deleting a record.
The issue you're running into is just the result of using OnPreInit to do data binding, so you're probably going to have to stop doing that, or try one of the sub-optimal approaches that others have suggested (redirecting back to the page after a postback).
Perform your data binding operations later in the page lifecycle, e.g. in the page PreRender event which fires after any control events have been handled.
You should just handle the click event. Then after your database update/insert, you must rebind your data. Depending upon your implementation, you might need to re-post the page. If you were to use normal data binding you could just call the bind method again.
Retrieve data on the Page.LoadComplete event and do a data bind.
If for some reason, should retrieve them only on PreInit, then retrieve them on for !IsPostBack condition and bind them and for PostBack conditions, handle them on LoadComplete
You could use this method to determine which control issued the postback in the PreInit: http://blogs.microsoft.co.il/blogs/gilf/archive/2010/03/01/discover-which-control-raised-a-postback.aspx