Question

I want to populate one drop down list based on the selection of another drop down list.

I know it’s a fairly common problem, and for two whole days I’ve been trying different samples that I find on the net, to no avail!

Here is my code:

controller:

 public List<SelectListItem> listTestCases(string id)
    {
        IQueryable<SelectListItem> A = repository.listTestCases(id);
        return (A.toList());
    }

    public JsonResult listTestCases_2(string id)
    {
        IQueryable<SelectListItem> A = repository.listTestCases(id);
        return Json(A);
    }

I have two methods, one of them returns a List, the other one JSONResults, and I tried everything I found on the net with both methods.
script:

<script>
$(document).ready(function() {
    $('select#testCategoriesUniqueId').change(function() {

        var testCategory = $(this).val();
        $.ajaxSetup({ cache: false });
        alert(testCategory);

        $.getJSON("TestInput/listTestCases/" ,  {id: testCategory}, function(data) {
            alert("here");
        });

    });
});

With the above code, the code goes through the listTestCases, and get’s the results, but It doesn’t go to the success function. (doesn’t alert)

I have tried:

 $.getJSON("TestInput/listTestCases/" + testCategory, null, function(data) {
            alert("here");
        });

not surprisingly same results.

I even tried : (json-p)

 $.ajax({
            url: "TestInput/listTestCases/" + testCategory,
            dataType: "json-p",
            success: function(data) {
                alert(data.length);
                var S = "";
                $("#testCasesUniqueId").removeOption(/./);
                for (var i = 0; i < data.length; i++) {
                    S += data[i];
                    var val = data[i].Value;
                    var text = data[i].Text;
                    $("#testCasesUniqueId").addOption(val, text, false);
                }
                alert(S);
            }
        }
        );

and the result is a string (System.collections.List[…SelectListItem]. and does not give me the objects of the list. so I tried it with listTestCases2, and it is not even calling the method.

I read somewhere that I need to use post instead of get, and I even tried postJSON. and no result.

Basically I’m super lost.

Answer 1

Somewhere I read that I need to use “post” method for my purpose.

 $.ajax({
            url: "TestInput/listTestCases_2/" + testCategory,
            dataType: "json",
            type: 'post',
            success: function(data) {
                alert(data.length);

            }
        });

Works for me.