I am using the Knockout: Contacts editor example http://knockoutjs.com/examples/contactsEditor.html as the template to start my MVVM project.
At the top of my page I have a set of cascading combo boxes that allow the user to drill down to a master record. When the user clicks the refresh button, an AJAX call finds the corresponding detail records from the server matching the user's search criteria. I load them into my viewmodel using ko.mapping.
My viewmodel is not as nested as the example, so I don't have anything at the "phone number" level. I do still want to add and delete records at the "first name / last name" level.
I am familiar with making AJAX calls to the server. I've looked at countless examples, but I still haven't found a good example of what the server side code should look like. Could someone point me toward an example that uses a list of objects like the example I am working with and what the VB.Net code looks like on the controller for adding, updating, and deleting database records using entity framework?
Related
Our SQL Server database has a huge number of data in different tables (millions of records) and we are populating the data using paging in the UI. Data is dynamically added and updated. Now I am planning to implement realtime filtering/searching of the data. The UI will have a text box where user types search keyword and the rows in the grid should be refreshed based on the search string as a typeahead functionality. I am thinking to use azure search as one of the candidate for implementing this functionality. But we are not on cloud yet and I have to justify my team if we had to go through this route.
Are there any other products or methods that can help in achieving this? I am still doing research on this. But if anyone has already implemented a solution like this, I would like to know more about your recommendations.
I recently started using https://datatables.net, and it's been a good experience.
Otherwise, you'll probably have to roll your own solution that keeps track of page and filter criteria on the client side and makes Ajax calls whenever they're altered. Your endpoint would need to take the page and filter as parameters, perform the necessary query of the data, and return the desired records.
I'm building a web application that has a particular model representing some events. Users need to be able to add N number of people to a given event. Choosing people is handled by a partial view.
I'm trying to build a menu that displays when users click "add a person" to the event. Because the event hasn't been filled out completely yet, there is nothing in the database to persist between requests.
I also have validation logic on the event page.
My proposed solution is to add the form to search or add for people on the event form itself and have a submit button that sends the values that have been added back to the server, where I can store them in ViewData or Session.
Unfortunately, doing this flags the validation.
My second solution is to load a partial view responsible for loading the UI to add/search for a person. I could add a little code on the method in the controller that returns a partial view storing the existing data in a session variable or viewdata. Trouble is, I have to submit the form to do it--again tripping the validation!!!
I'm wondering if perhaps I chose the wrong tool to do this...because in webforms, there would probably be a postback and you would just perform an operation on that postback. I'd like to avoid rewriting the application in webforms and am wondering if there are ways I'm overlooking in ASP.NET MVC.
Thanks in advance for the ideas!
I would probably have the partial view send it's data to the main page (with javascript). That way there is only one post to the server and it is when all of the data the user needs to enter has been filled out. How are you displaying the partial view? Is it on the main page (in a div), or is it a separate pop-up window? Either way, you should be able to use javascript to store this data on the main page and post all of the data back at one time.
HTH
I haven't even attempted this yet and am creating this question for advice really.
I have a strongly typed page which receives a form model composed of several components. It is to create a mitigating circumstance (MC) for a student at a university for my final year project. A MC can be composed of the initial problem, assessment extensions, and I use a multi select box to allow the user to select staff retrieved from the database which are able to view the MC once created.
The thing is I feel that a student could be granted many assignment extensions for one problem. I am wander if it is possible to include a button/image on the form which when clicked will create a new assessment extension object, and duplicate the form components to set the values for the object? This would all need to occur without any page refreshes.
Any advice, or links to good tutorials would be appreciated. I have so far been unable to find any suitable examples.
Thanks,
Jon
There are a number of ways to do this, but the fastest is to create a javascript handler which creates the form controls without any sort of server request, all you need to do is keep track of how many items are in your list so you can name the form controls correctly.
Start by making a button that when you click on it creates form controls. Once you get that, work on the naming.
I'm making a simple CRUD app with ASP MVC and I want to have a confirm page when creating a new object and inserting it into the database.
The problem is that I'm having trouble passing the object between actions. I tried to save it in the session after it's created and then retrieving it when the user confirms, but I'm getting an InvalidOperationException when I try to insert it into the database ( I'm using Entity Framework )
I'm not even sure if I'm approaching this the right way. Any ideas?
What I like to do if the schema allows for it, is to have an active flag (and timestamp field) on the record. You insert on the first page without setting that flag. The confirm page merely sets the active flag. Another process can clean dead records that were not confirmed within a certain range of their timestamp. And the object or entity never ties up session memory.
edit for clarity: as a result you only pass the id of the created entity to the confirm page
Tim's is the best basic answer to this but if you don't want to include the extra logic you could also consider using hidden fields on the confirm page so confirming actually resubmits the form data (this means less DB trips and means that you don't have old unconfirmed entries sitting in the DB to filter out but means more data to and from the client).
Another alternative that might be preferred from a UI point of view is to have Tim's answer but if JavaScript is enabled make the submit button instead pop up a confirm screen, clicking OK would submit both the form and the confirmation in one go.
using asp.net mvc, I'm initializing a list in the server code, and allowing the end-user to add to the list on the form (using JQuery to add entries). I know how to obtain a list's selected items on a post back, but I don't need to do that here. I want the complete contents of the list accessible in the server code after a post back.
Is a posted list just not going to give me the full content? Should I use Ajax to send each item to the server as each items gets added to the list?
thanks
There are a couple of ways that I can think of doing this.
make an ajax call each time an item is added - as you suggested
when an item is added to the list, you also add a hidden field to the form that will be submitted. Then on post back (although that terminology is very Web Forms-y), in your action method, you'll have access to the contents of the list. If you name things correctly you should be able to model bind to a List.
The latter would be my preference, it depends on your particular situation though.
Some things to keep in mind:
Bandwidth from the user to the web server is very small compared to bandwidth from a database to the web server
The database most likely cached whatever query you just ran to populate that list
It sounds like you're asking for the entire list to be included with the postback data, and that means having the browser upload that data for the user.
With all that in mind, it should be obvious that you're better off rebuilding your base list from the database.