Auto populate script tool parameter with layers in a map document

RoySP

Does any one know how to auto populate a script tool parameter with list of layers in a map document when the map document is provided as the first parameter.

This functionality is common when opening arctoolbox tools within a map document. The input dataset parameters automatically pick up the layers and tables in the table of contents.

I know that tool validation can be used to get the list of fields in a feature class. I did not have luck applying the same logic for list of layers in an mxd.

Thanks for your help!

jbarrette

You'll want to work with validation scripts.  You get to validation scripts by right-clicking on a script tool, go to properties, and selecting the validation tab.

Here is a sample script that updates a parameter with layer names once a map document

  def updateParameters(self):     """Modify the values and properties of parameters before internal     validation is performed.  This method is called whenever a parmater     has been changed."""          import arcpy     if self.params[0].value:       mxd = arcpy.mapping.MapDocument(self.params[0].value.value)       lyrs = arcpy.mapping.ListLayers(mxd)       layerList = []       for lyr in lyrs:         layerList.append(lyr.name)        uniqueList = list(set(layerList))       uniqueList.sort()              if not self.params[1].altered:         self.params[1].filter.list = uniqueList     return

There is an arcpy.mapping sample scripts download that has about 20 different script tools and several different validation scripts.

http://www.arcgis.com/home/item.html?id=18c19ec00acb4d568c27bc20a72bfdc8

The sample above is from the Replace Layer with Layer File example.

Jeff