[Attribute] UseOnlyInStep [Type] character_string [Required] No [Description] 
Specifies the stages for which the diagnostic service should include the parameter in the command. The possible values are PreStep, RunStep, PostStep, or any comma-separated list of two or three of these values. The default value of PreStep,RunStep,PostStep specifies all three stages. The Parameter element for the parameter that specifies the expected value for a comparison test often uses this attribute to prevent the diagnostic service from including the parameter in the commands for the PreStep and RunStep stages. In these circumstances, use a value of PostStep for the UseOnlyInStep attribute. You can only specify this attribute when the Parameters element that is the parent of this Parameter element is a child of the DiagnosticTest element. You cannot specify a value for this attribute when the Parameters element that is the parent of this Parameter element is a child of the PreStep, RunStep, or PostStep element.