Datepicker automatically causing a postback in ASP.NET

[hvjackson]

I use Datepicker with an ASP.NET Web Forms site. Version 1.4.1 worked fine for me but as of 1.5.0 I am noticing the following bug:

If an ASP.NET TextBox with the setting "AutoPostBack=true" is used as the base element for a Datepicker, the datepicker code automatically triggers a page postback, which causes the page to reload, which causes the postback to be triggered, etc. In other words, the page keeps refreshing indefinitely.

It is not easy to make a sample snippet of ASP.NET code but here is how I am creating a textbox:

        <asp:TextBox runat="server" ID="rangeStartBox" CssClass="input-small datepicker" AutoPostBack="true"/>

Normally that should trigger a POST only when the textbox is actually changed, but starting in 1.5.0 a POST is triggered every time the Datepicker is initialized.

[MrBenjaminRay]

I have been having the same issue. Setting AutoPostBack="false" prevents the unintentional postback, but you obviously lose AutoPostBack functionality.

When an instance of the plugin is created on a field, the plugin's constructor Datepicker() calls update(), which in turn triggers the jQuery change event on the input element by calling this.element.change(). This tells ASP.Net that the value has changed, triggering an ASP.Net PostBack.

I have worked around this issue as follows:

1) Update bootstrap-datepicker.js by changing line 826 (v1.6.0) from this:

    this.element.change();

to this:

    if (typeof preventDatePickerChange == 'undefined' || !preventDatePickerChange) {
        // Prevent change event if we're just initializing the plugin on a field
        this.element.change();
    }

2) Create and set the variable preventDatePickerChange to true before initializing the plugin on the field, then set it to false after. I do this everywhere I use the datepicker plugin. In an ASP.Net environment, this would have to be run every time the field is posted back.

    var preventDatePickerChange = true; // Initialize & set the variable to block change event
    $('some-selector').datepicker({
        // some options
    });
    preventDatePickerChange = false; // Set variable to allow all future change events

After making these changes, I no longer have any unwanted PostBacks, and I have yet to find any negative side-effects.

[AlucardKun]

Hi Guys,

I have the same problem in version 1.6.4.

To temporaly solve my problem, i commented the line 802 in bootstrap-datepicker.js:

from this:

this.fill();
this.element.change();
return this;

to this:

this.fill();
//this.element.change();
return this;

I did not see any negative impact on the page.

[Azaret]

Hi,
I think the main issue in this case if that the update event is triggered at startup, but should not, am I right ?

[MrBenjaminRay]

You are correct.

[MrBenjaminRay]

This is fixed in the upcoming version 1.7.0.

See the commit here: 110b120

[shivakadakol]

this.fill();
//this.element.change();
return this;

work fine