How to change WebGrid action for getting data (.NET MVC3) - asp.net-mvc-3

I have a Partial View that renders WebGrid. My controller looks like
public ActionResult Index()
{
return View();
}
public ActionResult GetUserList(int? page, string sort, string sortdir)
{
var model = UserModel.getList(page,sort,sortdir);
return PartialView("_UserList",model);
}
Index.cshtml :
....
#Html.Action("GetUserList")
The problem is that every time I click on grid navigation or sort links it calls Index method. How can I make Webgrid to execute a different action (GetUserList in this case)? I'm sure I can prepend GetUserList to all links in grid using jquery, but I believe it should be a better way.
It's also possible that what I'm doing is completely wrong, so thanks for your suggestions.

After lot of monkeying around and digging (and even fiddling with Reflector with WebGrid's source code), I came to the conclusion that with WebGrid, you cannot control/change the Header link action.
To create the header link URL, the path is taken from HttpContext.Request.Path, so there is no way to customize it to point to a different route.
One very ugly hack would be to tap into to jQuery Ajax's events (since the header link uses jQuery.load to sort) and overwrite the URL:
Album Id
Better solution would be to use:
Telerik Grid which lets you specify custom routes and also offers much more flexibility in rendering your layout
or MvcContrib Grid (not sure if this lets you modify header links but definitely offers more flexibility than WebGrid)

#MrChief had the idea above about the ugly hack...I put that together. Here is the main code that I used to do this. It does, indeed, hijack the ajax call before it is put on the wire. The key is to modify the URL that is getting sent because the grid will grab that URL from HttpContext.Request.Path. and plug it into the onclick for the anchor element.
I put this into my main common.js and will simply attach a function to capture the ajaxSend event which happens just before the data is sent.
// Used to hijack the sending of all AJAX calls. Before it sends the call to the server, it checks to see if the
// active element (the element that prompted the call) is marked with a given class. If so, then it will perform
// the given operation.
$(document).ajaxSend(function (event, jqXHR, ajaxOptions) {
var activeElement = document.activeElement;
if ($(activeElement).attr('redosorturl') != null) {
// If this is a sort anchor link from a grid that needs to have the sort link redone, do it here.
// the code is in the eipGrip.js file.
if ($(activeElement).attr('redosorturl').toString() == 'redoSortURL') {
var newURL = RedoGridSortURL(activeElement, ajaxOptions.url.toString());
ajaxOptions.url = newURL.toString();
}
}
return false;
});
When rendering the page, I have marked the tag in column header that contains the incorrect URL with a class named "redosorturl', so I know when I hijack the ajax call, the operation has to be done on this element. I then call a custom function that gives me the correct URL, then the ajaxOptions.url is then rewritten with that new URL.
I have to pass the activeElement to that rewrite function so I can traverse up the DOM to get the grid information, where I have put data like the controller and action method that is used along with and IDs and other info that I use for the URL. Likewise, I pass in the current url string because the grid will inject a token at the end of the url that I parse off and put on the new url.

Your conclusion isn't right. You just need to wrap your webgrid in a Get form:
using (Html.BeginForm("GetUserList", "ThingaMaBob", System.Web.Mvc.FormMethod.Get))
{
var grid = new WebGrid(
...
));
Html.Hidden(grid.SortFieldName, grid.SortColumn);
Html.Hidden(grid.SortDirectionFieldName, grid.SortDirection == SortDirection.Ascending ? "ASC" : "DESC");
}
The hiddens are so that the sort dir and sort field end up in parseable form in the querystring. You end up with urls like localhost/ThingaMaBob/GetUserList?someotherfields=whatever=&sort=city&sortdir=ASC

If you remove [HttpPost] attribute and let the route come to the same function. you'll find the Request["page"] value in your method. this will allow you to put a check on Request["Page"] value.

Related

How do i request an Array from the controller from inside a javascript code

I am using Spring boot, JPA with mysql, and thymeleaf and openlayers for the map.
So i have a map, and on this map there are dynamically generated markers for different places. What I want is when I click any of those markers to send the name of the marker to my controller and in response get an array of fishes that can be caught in this specific area and then display the names and pictures of the fishes in a dynamically generated list located on the sidebar . I cant think on how I can achieve that. Ive made a HTML page to show how I want it to look.
I was thinking about making a get request and giving the name as a path variable but then idk how I can do that request from the javascript when the button is clicked. Any ideas or concepts that I can read about are apreciated.
Most DOM elements in html are accessible in javascript via something like document.getelementbyid and typically if I remember this correctly most of the objects you can do something like domobject.addEventListener("click", myScript); and in myScripy make an http call to spring requesting the list of fish. I recommend setting some breakpoints in your JavaScript code via the dev console in your browser and looking through some of the objects that are produced
You can make a get request like described here. developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest
Clicking on the markers would be similar to this example https://openlayers.org/en/latest/examples/icon.html, but instead of showing a popup you make a GET request for more data
map.on('click', function (evt) {
const feature = map.forEachFeatureAtPixel(evt.pixel, function (feature) {
return feature;
});
if (feature) {
const name = feature.get('name');
// now make get request
// ....
}
});
If you are requesting an image you could use xhr as in https://openlayers.org/en/latest/apidoc/module-ol_Tile.html#~LoadFunction or you could use fetch, similar to:
fetch(url).then(function(response) {
if (response.ok) {
return response.blob();
}
}).then(function(result) {
if (result) {
const imagesrc = URL.createObjectURL(result);
}
});

Alternative for ViewData and QueryString

I have a page(a.aspx) to which im navigating from two different pages(ie there is a link in these two pages where it navigates to a.aspx)
to differentiate from which page i was navigated to a.aspx i used the below code.
passed Querystrings(B1,B2) to the target page as below
Html.ActionLink("test" "Testing", new { Controller = "Stats",prev="B1"},new { #class = "link",target="_self" })
Html.ActionLink("test" "Testing", new { Controller = "Stats",prev="B2"},new { #class = "link",target="_self" })
and in the action of the target page controller i used the below code
ViewData["prev"] = Request.QueryString["prev"].ToString();
and im using this ViewData in the target page ie a.aspx.This is working fine..
Im abit reluctant to use Query.string and ViewData for the above requirement.Please suggest any other alternative approach for the same.
You can use this,
Get the name of the controller
#ViewContext.Controller.ValueProvider.GetValue("controller").RawValue
Get the name of the action
#ViewContext.Controller.ValueProvider.GetValue("action").RawValue
I found that here.
Why not navigate to two separate actions that return the same view? Then, return a model to the view that will indicate the "from" page. You'll know which page you came from by virtue of which action gets hit. It's cleaner, far less complicated, and easier to maintain than trying to pass around this sort of thing in a querystring, viewdata, viewbag, etc. That being said, if you are having to do a lot of this sort of thing, creating separate actions each time around is not reali

implement chanied filters/seach options in a datagrid using ajax

Let´s say I have some sort of datagrid and I want to add a couple chained filters like in this site:
http://www.yelp.com/search?find_desc=bar&ns=1&find_loc=Minneapolis%2C+MN
(sort by,distance,price etc).
Each time a user clciked in a filter link it will update the content of datagrid accordingly. But I would also need to update the links in other filters to take account of the changes. Ex: if i change the order field I need to add/update ?order_field=x in all the other filters links.
What you think is the best way to implement such scenario?
Should i create a function that, when a filter link is clicked, it update the query string params of all the other filters? Or use hidden fields to record the selected option in each filter?
I would like a reusable solution if possible.
Since the data is loading via AJAX, there shouldn't be any links to update - at least not if you mean anchor tags <a>. You don't even need to store the filters in a hidden field.
I would store all the filters as a JSON object. Depending on how your API is set up, you may have to convert the JSON object to something usable by your API or you may even be able to pass on the JSON object directly in the $.ajax request.
This sample code assumes you have a textbox with id="price" in the markup. I intentionally left convert_filters_to_parameters blank because you didnt provide any details as to your API. jQuery will in turn serialize those parameters into a GET or POST request before it sends them out.
var filters = {
distance:null,
price:null,
sortBy:'distance'
}
//this assumes you have a textbox with id="price"
$('#price').changed(function()
{
filters.price = $(this).val();
refresh_data();
});
function refresh_data()
{
var parameters = convert_filters_to_parameters(filters);
$.ajax('/my_api',
{
//i left out a lot of properties here for brevity
data: parameters,
success: function(response) { alert(response); }
});
}

How to use partial views

I'm coming to a part in my MVC 3 page where I need to do a JQuery $.Ajax callback, but unlike before where I have returned some simple values and handled updating the UI using JQuery I need to refresh the part of the page that displays the main ViewModel data. So in effect it's almost as if I need to do a callback but instead of returning the JSonResult I want to return the original View?? I'm pretty sure though that I need to be thinking about using partial views? Could anyone advise or perhaps point me towards a good tutorial?
Thanks in advance.
If I understand correctly. In this sort of scenario I usually re-use the same action but return either a full or partial view based on the IsAjaxRequest method.
public ActionResult MyAction(string someParam)
{
//...
if (Request.IsAjaxRequest())
{
return PartialView(model);
}
else
{
return View(model);
}
}
This can then be called in jQuery using something like:
$("a.myAction").click(function (event)
{
event.preventDefault();
var button = $(this);
// Get more results using ajax
$.get(button.attr("href"), function (data)
{
// Add the new content
$('div#myActionResult').empty().html(data);
}, "html");
}
You may need to POST instead or change the Url to include a query string if you want to send data to the action to change the view.

JQuery - which form was submitted?

I have a page of products and for each of them, I want to have a form that uses AJAX to update the session. I've done this bit - just providing background.
I use the product's ID to create a different form class and name for each form, so each form is called something like this_form_name_567 and the next would be this_form_name_568 and so on.
There is a submit button per form. I'm having trouble figuring out
Which event is best to use so that the correct form will be identified when a submit button is clicked?
Once clicked, how to then make sure the correct value is taken from a hidden field (unique ID) within the submitted form so that I can populate a line of code such as:
$.post("compare_response.php", {compare_this: $("#compare_this").val()}, function(data){
}
You can use the .closest tree traversal method to get the form in which the button of interest is nested:
$("input[type=submit]").click(function() {
alert($(this).closest("form").attr("id"));
});
or even simpler, just get the element's form property :)
$("input[type=submit]").click(function() {
alert(this.form.id);
});
You can try it out here.
You can get the form you are submitting like this:
$('form').submit(function() {
var yourForm = $(this);
var hiddenValue = $(this).find('input[type=hidden]').val();
});
Of course you can get the hidden value differently, or if you have more than one hidden you'll have to give a little more information about it.

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