devextreme numberbox option set value programmatically

Daniel Parker

2 min read

·

24-02-2025

1

0

Share

DevExtreme's NumberBox is a versatile component for inputting numerical values. Often, you'll need to control its value from your JavaScript code, perhaps based on user actions or data fetched from a server. This article details how to programmatically set the value of a DevExtreme NumberBox. We'll cover different scenarios and best practices.

Accessing the NumberBox Instance

Before you can set the value, you need a reference to the NumberBox instance within your JavaScript code. This is typically done using the $("#numberboxID").dxNumberBox("instance") method, where numberboxID is the ID you assigned to your NumberBox in your HTML. Ensure you have included the DevExtreme scripts and configured your NumberBox correctly.

<input id="myNumberBox" type="number">

const numberBox = $("#myNumberBox").dxNumberBox("instance"); 

Setting the Value

Once you have the instance, setting the value is straightforward. Use the option("value") method, passing the new numerical value as an argument.

numberBox.option("value", 10); // Sets the value to 10

This will immediately update the NumberBox's displayed value.

Handling Events and Updates

Setting the value programmatically might trigger events within your application. For instance, if you have an onValueChanged event handler attached to your NumberBox, this handler will fire when the value is changed programmatically. Be mindful of this when designing your application logic.

$("#myNumberBox").dxNumberBox({
    onValueChanged: function(e) {
        console.log("Value changed to:", e.value);
    }
});

Setting Value Based on External Data

A common scenario is setting the NumberBox value based on data received from a server or another part of your application. This might involve an asynchronous operation.

$.ajax({
    url: "/api/data",
    success: function(data) {
        numberBox.option("value", data.numberValue);
    }
});

In this example, we fetch data from an API endpoint and then update the NumberBox's value accordingly. Remember to handle potential errors within the AJAX call.

Working with null or undefined Values

You can also set the NumberBox value to null or undefined to clear the displayed value.

numberBox.option("value", null); // Clears the NumberBox value

This is useful for scenarios where you need to reset the input field or indicate the absence of a value.

Best Practices

• Error Handling: Always include error handling when fetching data or performing other operations that could fail, especially when dealing with asynchronous calls.
• Data Validation: Before setting the value, validate the input to ensure it's a valid number within the NumberBox's allowed range. The NumberBox itself has built-in validation capabilities, but you might need additional client-side validation.
• User Experience: Provide clear visual feedback to the user when the NumberBox value is changed programmatically. For example, you might briefly highlight the changed value or display a confirmation message.

Conclusion

Programmatically setting the value of a DevExtreme NumberBox is a fundamental task in many applications. By using the option("value") method and understanding event handling, you can effectively manage and update the NumberBox's value dynamically, creating a more interactive and responsive user experience. Remember to incorporate best practices for error handling and user feedback to create a robust and user-friendly application.