javascript - Call ViewBag in Jquery to get the value from controller

Question

I am calling ViewBag.DeliveryDatebySupplier to update my textbox or just to alert. The value was always null. But when I debug and check the ViewBag in controller it has the date value.

Controller

if (ds.Tables[0].Rows.Count == 1)
{
    string dt = ds.Tables[0].Rows[0]["DeliveryDt"].ToString();
    DateTime myDate = Convert.ToDateTime(dt);
    dt =  myDate.ToString("yyyy-MM-dd");
    ViewBag.DeliveryDatebySupplier = dt.ToString();
    //Session["NewDeliveryDate"] = dt.ToString();                    
}

Jquery

function getDeliveryDateBySupplier() {
    var _storeID = $('#ddlStoreID :selected').val();
    var _SupplierID = $('#ddlSupplier :selected').val();

    var url = "@Url.Content("~/Home/DeliveryDatebySupplier")";

    $.ajax({
        data: {
             StoreID: _storeID,
             SupplierID: _SupplierID
        },
        type: 'POST',
        cache: false,
        dataType: 'json',
        url: url,
        success: function (result) {
            var newDeliveryDate = '@ViewBag.DeliveryDatebySupplier';
            alert(newDeliveryDate);
        },
        error: function (ex) {
            alert("Error getDeliveryDateBySupplier()");
        }
    });
}

question from:https://stackoverflow.com/questions/65648628/call-viewbag-in-jquery-to-get-the-value-from-controller

Answer 1

Assuming the action called DeliveryDatebySupplier in the HomeController is the method to set ViewBag.DeliveryDatebySupplier, then this will not work unfortunately.

The script will be generated when the full page was generated and at that time, the value would not have been set yet.

I would advise, rather than using the viewbag, return the value when DeliveryDatebySupplier is called in your script.

Controller will be something like this then

    if (ds.Tables[0].Rows.Count == 1)
    {
    string dt = ds.Tables[0].Rows[0]["DeliveryDt"].ToString();
    DateTime myDate = Convert.ToDateTime(dt);
    dt =  myDate.ToString("yyyy-MM-dd");
    return new JsonResult
    {
        data = new
        {
            DeliveryDatebySupplier = dt.ToString()
        }
    };                     
    }

and jquery would change to something like this

success: function (data) {
 if (data) {
    var newDeliveryDate = data.DeliveryDatebySupplier
    alert(newDeliveryDate);
}
else {
    //Error
}
},