动态添加有javascript的字段，形成

Question

I have added fields to my form dynamically using a for-loop, which works fine. However, the fields i'm adding are supposed to be DatePickers and they require javascript as well. I've tried giving them a unique ID from the integer that the loops iterates through, but it does not seem to find them?

This is the view:

@model ProjectName.Models.ViewModels.GuestCreatorViewModel
@using Res = ProjectName.Resources.Resources

@for (int i = 1; i <= Model.NumOfGuests; i++)
{
    <div class="row">
        <div class="form-group">
            @Html.Label(Res.Name, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.TextBoxFor(model => model.Name, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.Name, "", new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.Label(Res.Period, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.TextBoxFor(model => model.DateRange, new { id = "dateRangePicker" + i, htmlAttributes = new { @class = "form-control" }, @readonly = true })
                @Html.ValidationMessageFor(model => model.DateRange, "", new { @class = "text-danger" })
            </div>
        </div>
    </div>

    <script type="text/javascript">
        $('input[name="dateRangePicker'+@i'"]').daterangepicker();
        $('#dateRangePicker'+ @i'').daterangepicker({
                "showWeekNumbers": true
            }, function (start, end, label) {
                console.log('New date range selected: ' + start.format('YYYY-MM-DD') + ' to ' + end.format('YYYY-MM-DD') + ' (predefined range: ' + label + ')');
            });
    </script>
}

If I remove the "+ @i" in the javascript and "+ i" in the html.helper it works for the first row, but all rows/fields after does not work (I guess because the script is outside their scope). If I keep them, none of the fields work with the script.

Am I doing something wrong when dynamically naming them or something?

The DateRangePicker is taken from here , but I've also tried other datepickers where the same issue occurs.

Answer 1

I would not use the ID to assign the datepicker but a css class (even a not defined one, just for this purpose). So you code could be something like this:

@class = "control-label col-md-2 ToBeDatePickered"

So you could try and use this simple selector:

$(".ToBeDatePickered").daterangepicker();
// ... and so on...

And the JS code should be outside the for statement, maybe in a document.ready function like this:

<script type="text/javascript">
        $(document).ready(funtion() {
             $(".ToBeDatePickered").daterangepicker();
             // ... and so on...
        });
</script>

Hope this helps

Answer 2

First : This syntax is incorrect:

@Html.TextBoxFor(model => model.DateRange, new { id = "dateRangePicker" + i, htmlAttributes = new { @class = "form-control" }, @readonly = true })

It will render this useless attribute: htmlAttributes It should be:

@Html.TextBoxFor(model => model.DateRange, new { id = "dateRangePicker" + i, @class= "form-control", @readonly = true })

I guess it is a typo.

Second: What you should do is generate all your HTML in the for loop, and use a single script tag after that to initialize the daterangepicker controls at once. You can get all inputs with a class instead of using their ids.

@{
        int numOfGuests = 2;
    }
    @for (int i = 1; i <= numOfGuests; i++)
    {
        <div class="row">
            <div class="form-group">

                <div class="col-md-10">
                    @Html.TextBoxFor(model => model.DateRange, new { id = "dateRangePicker" + i, @class = "form-control custom-date-picker" , @readonly = true })
                </div>
            </div>
        </div>
    }
<script type="text/javascript">
    $('input.custom-date-picker').daterangepicker({
        "showWeekNumbers": true
    }, function (start, end, label) {
        console.log('New date range selected: ' + start.format('YYYY-MM-DD') + ' to ' + end.format('YYYY-MM-DD') + ' (predefined range: ' + label + ')');
    });
</script>

Explanation:

1. Upon creating the datepickers I add to each one a custom css class: custom-date-picker
2. After the for loop renders the HTML I create a script tag and get all inputs with the selector .custom-date-picker and create daterangepicker controls out of them

PS I used a simplified version of your code for the sake of explanation.