Question

I’ve got a jqgrid (version 3.5.3) on my site which gets its results from an ajax call to a web service. Often the query is complicated and it takes a few seconds to load the result. While it is loading the user sees a box [Loading…].

In case the users realise they’re searching for the wrong thing, the client has asked to add a cancel button to the grid, which would:

1. make the grid forget about the data it’s just requested
2. retain the results already loaded from the previous search

There doesn’t seem to be anything built in for this, so I’m probably looking for a bit of a hack to achieve this.

Any ideas?

Answer 1

Here’s our solution, which is very similar to Oleg’s, the main difference is that we keep track of a list of XHRs to make sure we clean all requests up

var handlerUrl = '';

jQuery(document).ready(function() {
    var xhrList = [];

    var beforeSendHandler = function() {

        var cancelPendingRequests = function() {
            jQuery.each(xhrList, function() { this.abort(); });
            xhrList = [];
            return false;
        };

        var hideLoadingUI = function() {
            $(this).hide();
            $("#load_list").hide();
        };

        cancelPendingRequests();

        $("#load_list").show();

// some faffing around to ensure we only show one cancel button at a time
        if (jQuery("#cancelrequest").length == 0) {
            jQuery(".ui-jqgrid-titlebar").append(jQuery("<button   id='cancelrequest'>Cancel</button>").click(cancelPendingRequests).click(hideLoadingUI));
        } else {
            jQuery("#cancelrequest").show();
        };  
    }


    jQuery("#list").jqGrid({
        datatype: function(postdata) {

            GetSearchCriteria(); //needed for the grid's filtering

            var xhr = $.ajax({
                //we override the beforeSend so we can get at the XHRs, but this means we have to implement the default behaviour, like showing the loading message ourselves
                beforeSend: beforeSendHandler,
                dataType: "xml",
                data: postdata,
                success: function(xmlDoc) {
                    //
                    jQuery("#cancelrequest").hide();
                    $("#load_list").hide();
                    jQuery("#list")[0].addXmlData(xmlDoc);
                    xhrList = [];
                }

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