Alright, let's tackle the intricate problem of updating parameters within a Key Schedule and, crucially, retrieving the ElementIds associated with each row. This is a common challenge for Revit API developers seeking to automate and manage data within key schedules.
Understanding the Challenge
Key schedules in Revit are fundamentally different from regular schedules. They don't directly list model elements. Instead, they define parameter values that can be assigned to elements through a "key" parameter. This creates a powerful system for managing consistent property sets.
The core issue is that the Revit API doesn't expose a direct "row" object in a key schedule that provides ElementIds. Instead, we must work with the KeySchedule element and its associated TableData and TableCell objects, along with the element parameter that references the key.
Solution Breakdown
-
Retrieving the Key Schedule:
- First, we need to obtain the
KeySchedule element from the Revit document. This can be done by filtering for schedules or by iterating through the document's elements.
-
Accessing Table Data:
- The
KeySchedule element has a GetTableData() method that returns a TableData object. This object contains the table's structure, including rows and columns.
-
Iterating Through Rows:
- We can iterate through the rows of the
TableData using its GetSectionData(SectionType.Body).GetNumberOfRows() and GetCell(row, column) methods.
-
Identifying the Key Column:
- We need to find the column that holds the key parameter value. This is typically the first column, but it's best to verify by checking the column's header or the associated parameter.
-
Retrieving the Key Value:
- For each row, extract the key value from the identified key column's cell.
-
Finding Elements with the Key Parameter:
- Use a
FilteredElementCollector to find all elements that have the key parameter.
- Apply a
ParameterFilter to filter for elements where the key parameter's value matches the key value extracted from the schedule row.
-
Updating Parameter Values:
- Once you have the
ElementIds of the elements matching the key row, you can access their parameters and update them as needed.
Code Example (C#)
Explanation:
- The code iterates through each row of the key schedule.
- It retrieves the key value from the first column.
- It uses a
FilteredElementCollector and ElementParameterFilter to find elements with the matching key value.
- It then updates the specified parameter (
parameterToUpdate) on those elements with the newValue.
Important Considerations:
- Error Handling: Add robust error handling to handle cases where the key schedule, parameter, or elements are not found.
- Transaction Management: Always perform parameter updates within a transaction to ensure data integrity.
- Performance: For large models, consider optimizing the
FilteredElementCollector to improve performance.
- Key parameter identification: In cases where the key parameter is not the first column, you must add code to iterate the ScheduleFields, and identify the correct ParameterId.
- Parameter types: Ensure that the parameter you are updating is of the correct type. If you are updating a number, or an elementId, then you must adjust the parameter.Set() method accordingly.
Retrieving ElementIds
The code example above effectively retrieves the ElementIds of elements associated with each key schedule row. You can store these ElementIds in a List<ElementId> or a Dictionary<string, List<ElementId>> (where the key is the key schedule row's key value) for further processing.
This approach provides a solid foundation for managing and updating key schedule parameters. Remember to adapt the code to your specific needs and always prioritize robust error handling and performance optimization.
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