Comboboxes are kind of finnicky. Try baby stepping it...Replace any code contained in any of the combobox methods with a pass statement:
class MyComboBox(object):
"""Implementation for MyComboBox"""
def __init__(self):
self.editable = True
self.enabled = True
self.dropdownWidth = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
self.width = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
def onSelChange(self, selection):
"""Occurs when the user makes a selection from the ComboBox drop-down menu"""
pass
def onEditChange(self, text):
"""Occurs when the user manually enters text into the ComboBox"""
pass
def onFocus(self, focused):
"""Occurs when the user clicks on the Combobox, giving the ComboBox focus"""
pass
def onEnter(self):
"""Occurs when the user presses the 'Enter' key while the ComboBox has focus"""
pass
def refresh(self):
"""Occurs after a value is established within the ComboBox"""
self.refresh()
Next, let's just make sure we can get the combobox to dynamically populate with a list of layers in the TOC when given focus
def onFocus(self, focused):
"""Occurs when the user clicks on the Combobox, giving the ComboBox focus"""
# Empty the Combobox items list
self.items = []
# Establish a reference to the current MXD
mxd = arcpy.mapping.MapDocument("Current")
# Establish a reference to the first DataFrame object in the current MXD
df = arcpy.mapping.ListDataFrames(mxd)[0]
# Build a List of LayerObjects contained in the first DataFrame of the current MXD
Layers = arcpy.mapping.ListLayers(mxd, "*", df)
# Iterate through the Layers
for Layer in LayerList:
# Append the current Layer's name to the Items List
self.items.append(Layer.name)
Once onFocus() has been invoked and you have a list of layers populating dynamically in the Combobox, we can begin thinking about what we want to do with the Selection in the Combobox. That's where the onSelection() and onEnter() events come into play. onEditChange() is really just another method of making a selection by allowing the user to type values directly into the box. Valuable when your item list is really long, so that the user doesn't have to scroll through values. For this though, we'll just focus on the onSelection() method.So now that we can make selections in the Combobox, what do we want to do with them? Let's look at onSelection()
def onSelChange(self, selection):
# Because 'mxd' and 'df' weren't given global scope, we have to reestablish them
# in order to use them in this method
mxd = arcpy.mapping.MapDocument("Current")
df = arcpy.mapping.ListDaaFrames(mxd)[0]
# Reference the first Layer in the DataFrame of the MXD which has a name that matches
# the current selection
layer = arcpy.mapping.ListLayers(self.mxd, selection, df)[0]
desc = arcpy.Describe(layer.dataSource)
extent = desc.Extent
fishnet = arcpy.CreateFishnet_management(r'in_memory\fishnet',
'%f %f' %(extent.XMin, extent.YMin),
'%f %f' %(extent.XMin, extent.YMax),
0, 0, 10, 10,
'%f %f' %(extent.XMax, extent.YMax),
'NO_LABELS',
'%f %f %f %f' %(extent.XMin, extent.YMin, extent.XMax, extent.YMax), 'POLYGON')
arcpy.RefreshActiveView()
I would encourage you to implement each of these in baby steps, rebuilding and testing the addin after each change so that if you do find problems, you know where to look. Print statements can also come in very handy for this purpose.
