Here are five things everyone should know about property expressions:
- The runtime evaluates and applies property expressions only at certain times:
- When loading
- When saving
- When the runtime calls validate on tasks
- When the runtime calls execute on tasks
- When a component calls AcquireConnection on connection managers
- When a component calls GetEnumerator on foreach enumerators
- They're available for almost all task, foreach enumerator, log provider, and connection manager writable properties.
- They're available on a limited number of dataflow component properties.
- They may not be used to modify variables.
- They're automatically provided for all writable properties on custom components except for custom Data Flow task components.