You can specify variables in the following message exchange activities:

• The Input field (for an inputVariable attribute) and Output field (for an outputVariable attribute) of an invoke dialog

• The Input field (for a variable attribute) of a receive activity

• The Output field (for a variable attribute) of a reply activity

The variables referenced by these fields typically must be message type variables in which the QName matches the QName of the input and output message types used in the operation, respectively.

The one exception is if the WSDL operation in the activity uses a message containing exactly one part that is defined using an element. In this case, a variable of the same element type used to define the part can be referenced by the inputVariable and outputVariable attributes, respectively, in the invoke activity or the variable attribute of the receive or reply activity.

Using a variable in this situation must be the same as declaring an anonymous, temporary WSDL message variable based on the associated WSDL message type.

Copying element data between the anonymous, temporary WSDL message variable and the element variable acts as a single virtual assign activity with one copy operation whose keepSrcElementName attribute is set to yes. The virtual assign must follow the same rules and use the same faults as a real assign activity. Table 6-6 provides details.

For more information about the keepSrcElementName attribute, see keepSrcElementName Attribute.