In this article, we will give an implementation of UserService that, when used in a user task, allows the user to update a workflow data context variable.
Before reading this article you should be aware of the UserService API.
Please see links in "reference" section.

In our example, we use a simple workflow that has one data context variable "myVariable", which default value is "initial_value":

Configuration

Input parameters:

• Dataspace: can be left empty
• Snapshot: can be left empty
• Data context variable, mandatory: it is the data context variable that will be updated in this user task
• Disable Accept at start: by default, the Accept button will be automatically displayed at the opening of the work item. If the value is 'true', the Accept button will be displayed as soon as the field is updated

Output parameter:

• Data context variable, mandatory: it is the data context variable that will be updated in this user task. At the end of the work item, the variable will be updated with the new value

Results

• Previous variable value: it contains the data context variable value at the beginning of the work item (not editable)
• New variable value: this is where the user sets the new data context variable value. If this form was previously saved in this interaction, the default value is the last saved value

User services documentation:

• Overview
• Quick start
• Implementing a user service
• Declaring a user service