# Dynamic binding

> [HTML Version](dynamic-binding.html)

This service widget allows you to use dynamic properties whose number and type are not known in advance. You can get such data using a script from an external service or server and store it in a variable of the [Arbitrary type](360009707032.md#arbitrary-type).

The **Dynamic binding** widget displays the contents of this variable as input and output values that can be mapped to the current context. It is available only on custom forms:

- In the settings of the [Business process activity](extention-activities.md) with the **Script **type.

**(dynamic-binding-1.png)**

- In the custom widget settings.

**(dynamic-binding-2.png)**

## Working with dynamic data

Perform the following steps when configuring a custom activity in a business process diagram or a custom widget:

1. Use a script to request variables from an external system. For example, you can get company data from an external service.

2. Save the retrieved data in a variable of the **Arbitrary type**.

3. On the custom settings form, the** **data from the variable of the **Arbitrary type** are displayed as input and output values through the **Dynamic binding **widget. The system administrator can map the values to the current context.

## Configure the Dynamic binding widget

The configuration steps for the **Dynamic binding **widget for an activity of the **Script **type** **or a custom widget are similar.

Let's look at the configuration steps using the custom **Calculator** widget, which performs an accounting operation. A script requests the number and types of operation parameters from the server. To display these parameters in the widget settings: 

1. Open the **Calculator** widget builder and [create a settings form](user-widgets-context.md#settings). The **Dynamic binding **widget is available only on the custom form. The settings form builder opens.

2. On the **Context **tab, add a variable of the **Arbitrary type**, which will store the data retrieved from the server by the script.

3. On the **Scripts** tab, add a script to retrieve data from an external system and save it in a variable of the **Arbitrary type**.  
For example, you can specify a script to initialize the widget settings form. When the ready-made **Calculator** widget is placed on a form or page, its settings open and the specified script runs.

4. Go to the **Template** tab and place the **Dynamic binding **widget** **on the modeling canvas. This widget displays data from the variable of the **Arbitrary type**. You should map them with the form or page context. Configure the widget:

**(dynamic-binding-3.png)**

- **Context\*** is populated automatically.

- **Dynamic fields\***. Select the property of the **Arbitrary type **from the context of the **Calculator **widget.

5. Save the settings of the **Dynamic binding **widget.

6. Save the settings of the **Calculator **widget form.

For more examples of using the **Dynamic binding ** widget, see the following articles:

- [Create a widget with dynamic context](widget-with-dynamic-context.md).

- [Binding variables for activities in business processes](activities-features.md#script).