NULL values while passing JSON data to controller via AJAX

Question

Trying to pass following JSON from View to Controller

{
    "allselected": false,
    "selectedIds": ["", "all"],
    "targetControl": "Studieniva",
    "targetSource": "studienivalist",
    "dependency": [{
        "name": "ShopNo",
        "selectedvalues": "311"
    }, {
        "name": "Institution",
        "selectedvalues": ["all", "UIO"]   // THIS IS COMING AS NULL AT CONTROLLER  . OCCURS ONLY WHEN MULTIPLE ITEMS UNDER dependency
    }]
}

Javascript code for sending request is like below (trying to make multiple requests at the same time and based on the response of each request loading some dropdowns )

        var targetcontrols_array = targetControl.split(',');
        var targetsource_array = targetSource.split(',');
        const arrOfPromises = targetcontrols_array.map(function(item, index) {
            var control_name = item;
            var source = targetsource_array[index];
            var request_data = JSON.stringify({ allselected: allselected_flag, selectedIds: selectedvalues, targetControl: control_name, targetSource: source, dependency: dependencyOptions });
            console.log("req:"+request_data); //SAMPLE JSON ADDED On TOP
            return new Promise((resolve) => {
                $.ajax({
                    url: action_url,
                    type: 'POST',
                    traditional: true,
                    async: false,
                    data: request_data,
                    contentType: "application/json; charset=utf-8",
                    dataType: 'json',
                    success: function (response) {
                       //process response
                    }
                })
            });
        });
        Promise.all(arrOfPromises);

MVC controller action is like below

 [HttpPost]
 public JsonResult CascadingDropDown(DynamicFormSelectModel model)
 {
     model.dependency  values are not coming correctly . Observing that the value of SelectedValues is NULL in some cases
     ( OCCURS ONLY WHEN MULTIPLE ITEMS UNDER dependency )
 }

public class DynamicFormSelectModel
{
    public bool allselected { get; set; }
    public string[] selectedIds { set; get; }
    public string targetSource { set; get; }
    public string targetControl { set; get; }
    public List<DynamicFormDependencyOptions> dependency { set; get; }

}
public class DynamicFormDependencyOptions
{
    public string Name { get; set; }
    public string SelectedValues { get; set; }
}

While trying to read the request model.dependency values , sometimes getting NULL , even if values are passed from View (Example attached JSON passing 2 values "name": "Institution", "selectedvalues": ["all", "UIO"] , but in controller i am getting NULL . OCCURS mostly WHEN MULTIPLE ITEMS are present under dependency property and no idea why its coming as NULL

[How to handle both a single item and an array for the same property using JSON.net](https://stackoverflow.com/questions/18994685/how-to-handle-both-a-single-item-and-an-array-for-the-same-property-using-json-n) — Drag and Drop, Oct 29 '19 at 07:13
Possible duplicate of [How to handle both a single item and an array for the same property using JSON.net](https://stackoverflow.com/questions/18994685/how-to-handle-both-a-single-item-and-an-array-for-the-same-property-using-json-n) — Drag and Drop, Oct 29 '19 at 07:16

score 0 · Accepted Answer · answered Oct 29 '19 at 05:54

    public class DynamicFormDependencyOptions
{
    public string Name { get; set; }
    public string SelectedValues { get; set; }
}

change it to

public class DynamicFormDependencyOptions
    {
        public string Name { get; set; }
        public string[] SelectedValues { get; set; }
    }

this code has the SelectedValues as string object but the data is in string Array form make SelectedValues a string Array and You'll get it .... and change your following code accordingly to parse the string array like you are doing for selectedIds.

NULL values while passing JSON data to controller via AJAX

1 Answers1