Updating the change event of the Kendo UI Dropdownlist

Question

Updating the change event of the Kendo UI Dropdownlist

I've been attempting to modify the "change" event of a Kendo UI Dropdownlist without success. Here is the code I have tested:

Below is the initialization code for my dropdownlist:

var onChange = function(e)
{
    alert("something changed");
};
// Initializing DropDownList from input HTML element
$("#dropdown").kendoDropDownList({
    dataTextField: "text",
    dataValueField: "value",
    dataSource: data,
    index: 0,
    change: onChange
});

Here is my attempt to update that function later on:

onChange = function(e){alert("attempt 1");};
var dropDownData = $("#dropdown").data("kendoDropDownList");
dropDownData.options.change = function(e){alert("attempt 2");}
dropDownData.refresh();

In my first attempt, I tried changing the onChange function directly. When that didn't work, I attempted to edit the options.change function. Although I successfully modified the options.change function in the Chrome debugger, the functionality of the dropdownlist remained the same. It seems like I need to refresh the dropdownlist to apply my changes effectively. Can someone advise me on how to refresh the kendo grid and display my updated data?

javascript asp.net asp.net-mvc kendo-ui

Answer 1

Answer №1

It seems like you already found a solution, but I wanted to provide some additional clarifications.

The reason why modifying it in this way

onChange = function(e){alert("attempt 1");};

does not work is because you are passing a function to the widget, which calls that function at specific times. You are not passing a reference to the variable onChange, so changing the variable will not impact the widget.

The reason why

dropDownData.options.change = function(e){alert("attempt 2");}

does not work is because Kendo stores handlers in its own structure (necessary for binding multiple handlers for the same event), so it does not execute whatever is in options.change instantly.

However, there is a method called setOptions, using which you could have made your second approach successful:

dropDownData.setOptions({
    change: function (e) {
        alert("attempt 2");
    }
});

Answer 2

It seems like you already found a solution, but I wanted to provide some additional clarifications.

The reason why modifying it in this way

onChange = function(e){alert("attempt 1");};

does not work is because you are passing a function to the widget, which calls that function at specific times. You are not passing a reference to the variable onChange, so changing the variable will not impact the widget.

The reason why

dropDownData.options.change = function(e){alert("attempt 2");}

does not work is because Kendo stores handlers in its own structure (necessary for binding multiple handlers for the same event), so it does not execute whatever is in options.change instantly.

However, there is a method called setOptions, using which you could have made your second approach successful:

dropDownData.setOptions({
    change: function (e) {
        alert("attempt 2");
    }
});

Answer 3

Answer №2

My solution involved implementing a simple workaround. Instead of the initial line, I decided to go with

change: onChange

It turned out that Kendo actually hardcoded the function body directly into the dropDownData.options.change function, rather than utilizing my specified JavaScript function. The debugger displayed it like this:

function(e)
{
  alert("something changed");
};

To resolve this issue, I opted for using an anonymous function within the Kendo call. Thus, I modified change: to

change: function(e) { onChange(e) };

By making this adjustment, when I later updated onChange, Kendo correctly referenced the designated JavaScript function and executed the latest version. For a live demonstration, you can check out this link:

Answer 4

My solution involved implementing a simple workaround. Instead of the initial line, I decided to go with

change: onChange

It turned out that Kendo actually hardcoded the function body directly into the dropDownData.options.change function, rather than utilizing my specified JavaScript function. The debugger displayed it like this:

function(e)
{
  alert("something changed");
};

To resolve this issue, I opted for using an anonymous function within the Kendo call. Thus, I modified change: to

change: function(e) { onChange(e) };

By making this adjustment, when I later updated onChange, Kendo correctly referenced the designated JavaScript function and executed the latest version. For a live demonstration, you can check out this link:

Updating the change event of the Kendo UI Dropdownlist

Answer №1

Answer №2

Similar questions

Invalid Blob URL functionality on Android web browsers

Webpack in Vuejs does not have access to the keys defined in dev.env.js file

Using Rails image_tag helper within a ReactJs application

Fetch a single random profile image from a Facebook user's list of friends using Javascript

Utilize Ag Grid to selectively apply borders between grouped values

What is the process for customizing the appearance of a prop within the <TextField> component?

Last month's display is currently unidentified

"Enhancing HTML tables with jQuery for a polished look

Are you utilizing the .Ajax() method in JQuery?

Looking for a way to incorporate an image source property into a larger image?

What is the best way to store temporary files across multiple executions in Node.js?

Is there a way to adjust the scrollLeft of a div according to the clientX position during a

Retrieve a JSON array using asynchronous JavaScript and XML (AJAX)

The Directive cannot be refreshed as a result of the ongoing "$digest already in progress" error

The invokeApply parameter within $interval remains unchanged and has no effect

What is the best way to restrict input to only numbers and letters in Vue Js?

Implementing bidirectional data binding with Semantic UI's search dropdown feature in Vue.js

JQuery Collapsible with embedded slider toggle switch

Dealing with the percentage sign in table names during data retrieval

$timeout once the method has finished executing