Using ArcGIS Pro SDK (C#), how can I add a layer (shapefile) from one map frame to another map frame in the same layout. I want to add a project area shapefile (c:\project1\projectArea.shp) from my "Main Map" map frame the "Overview Map" map frame. I already have both of these map frames in my layout. Pretty much, I want to copy and paste the "projectArea" shapefile from one map frame and add it to another, so that it shows up in my inset overview map. I am using ArGIS Pro SDK C#.
Map frame that contains the shapefile: "Main Map"
Map that contains the shapefile: "Map"
Map frame that I want to add the shapefile to: "Overview"
Map within the map frame that I want to add the shapefile to: "Overview Map"
Path to shapefile: c:\project1\projectArea.shp
You don't add layers to MapFrames, you add layers to Maps. MapFrames display the contents of an associated Map and preserve a specific extent.
Check out this help snippet on how to add a shapefile to a map.
Adding a layer to a map will automatically get displayed in any map frame that references that map.