Adding layers with subtypes and feature templates using ArcPy?

Question

I am trying to clip a feature from one geodatabase into another and retain the editing feature templates I have assigned using subtypes for the original feature class in the original geodatabase. After clipping, the subtypes and editing feature templates are retained, but only when I drag and drop the layers into the map document. When I use arcpy.mapping.AddLayer(), the editing templates are lost.

How do I use python to add layers such that the editing feature templates are retained?

The clipped feature is named "Feature_Clip" in the code below.

workspace = arcpy.env.workspace
clippedFeature = os.path.join(workspace, "Feature_Clip")
mxd = arcpy.mapping.MapDocument("CURRENT")
df = mxd.activeDataFrame
layer = arcpy.mapping.Layer(clippedFeature)
arcpy.mapping.AddLayer (df, layer)
arcpy.ApplySymbologyFromLayer_management(layer.name, layerFile)
del mxd, df, layer

note layerFile points to a .lyr file I have created from the original feature class in hopes of using it's symbology, but it doesn't seem to have any effect.

Answer 1

The way that I would try to do this would be to switch the feature class under the layer that you clipped by setting lyr.dataSource to your clipped feature class.

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The asker used this answer to resolve this. See updated code below for their final working solution. Note the layer name of the original is "Feature" in this example:

workspace = arcpy.env.workspace
clippedFeature = os.path.join(workspace, "Feature_Clip")
mxd = arcpy.mapping.MapDocument("CURRENT")
df = mxd.activeDataFrame
layer = arcpy.mapping.Layer(clippedFeature)
for existingLayer in arcpy.mapping.ListLayers(mxd, "", df):
 if existingLayer.name == layer.name[-5]: #Remove '_Clip" from new layer name to find original layer
 workspace_type = "FILEGDB_WORKSPACE"
 dataset_name = clippedFeature
 existingLayer.replaceDataSource(workspace, workspace_type,
 dataset_name)
arcpy.RefreshActiveView()

• Erik: Thanks PolyGeo, this worked but I used the replaceDataSource() method instead of setting its attribute as you suggested. I've edited my question with the working code.