ArcGIS Pro 2.6 API Reference Guide
SetMapSeries Method
Example 

ArcGIS.Desktop.Layouts Namespace > Layout Class : SetMapSeries Method
Sets the map series for a layout. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public void SetMapSeries( 
   MapSeries mapSeries
)
Public Sub SetMapSeries( _
   ByVal mapSeries As MapSeries _
) 

Parameters

mapSeries
Exceptions
ExceptionDescription
This method must be called within the lambda passed to QueuedTask.Run.
Remarks
This will either associate a new map series to a layout or override an existing map series already associated with the layout because a layout can only have one map series active at a time. This method will automatically call RefreshMapSeries.
Example
//Change the properities of a spacial map series.

//Perform on the worker thread
await QueuedTask.Run(() =>
{
  layout.SetMapSeries(SMS);
});
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

Layout Class
Layout Members