Set & Change a Value for Different Activities - Studio 8 Guide

1 Introduction

This document describes how to set and change values for various activities in microflows of Mendix Studio.

You need to assign a value to an object/variable, when you configure the properties of the following activities:

Create Object – you can create an object with this activity and provide initial values for properties of the object
Create Variable – you can create a variable and assign a value to it with this activity

You can also change the value when you configure the following activities:

Change Object – can be used to change an existing object or properties of this object
Change Variable – change the value of an existing variable in the current microflow

You can also configure a return value for the End Event – the location where the microflow will stop.

For more information on the functions of these activities, see Microflows.

To set the initial value or change the value of an object, do the following:

Add the Create Object/Change Object activity to a microflow. For more information, see the Adding New Event or Activity section in Microflows.
Click the activity to view its properties.
Select the data source for the activity, then click Add New Value
In the Set initial value/Change value dialog, select an attribute or association.
Set the initial value (for Create Object) or assign a new value (for Change Object) in Variables/Attributes, Constant, or Expression tabs. For more information on these tabs, see the Common Elements section.

To set the initial value or change the value of a variable, do the following:

Add the Create Variable/Change Variable activity to a microflow. For more information on how to add an element to a microflow, see the Adding New Event or Activity section in Microflows.
Click the activity to view its properties.
Select the data type for the activity, then click Set initial value / Change value
Set the initial value (for Create Variable) or assign a new value (for Change Variable) in Variables / Attributes, Constant, or Expression tabs. For more information on these tabs, see section Common Elements section.

The return value is the value that is returned to the flow or a widget that called the current flow. To configure the return value, do the following:

Add the End Event to a microflow or select the existing end event. For more information, see the Adding New Event or Activity section in Microflows.
Click the event to view its properties.
Set the Returns option to Value.
Select the data type, then click Value to configure it.
Set the return value in Variables/Attributes, Constant, or Expression tabs. For more information, see the Common Elements section.

You can see the following common elements when configuring the value:

The functions of these tabs are described in the table below:

Tab	Description
Variables/Attributes	Shows variables and attributes that match the type of an attribute, association, or variable that you want to create or change. For example, when you select an attribute of the type Decimal, variables of types Decimal and Integer will be shown in the tab. This happens because decimal can include whole numbers (integer). However, if you pick an attribute of the type Integer, variables of the type Decimal will not be shown, because the whole numbers (integer) cannot contain decimals. For more information on attribute types, see Attributes. Note The attribute of the type Long will be shown as Integer in microflows.
Constant	With this tab you can assign a new value selecting it from the values of an attribute of enumeration type.
Expression	With this tab you can assign an attribute, association, or variable different values, depending on what you write in the expression. For more information on expressions, see Microflow Expressions.