FAQ:  What happens when the Open or Save dialog is cancelled within the pythonaddins module?

【解决方案】
The cancel operation returns the 'NoneType' object (None). This is similar to the boolean objects of True and False.



In addition to the dialog function, there is the MessageBox function which has a variety of button options based upon its defined type. This function returns a string value representing the message button pressed (i.e., 'Cancel', 'Ignore', 'Continue').


An 'if' clause can be used to determine the next steps within the Python code after a button is clicked. For example:

import arcpy

import pythonaddins



class Open(object):

    """Implementation for Dialog_addin.OpenButton (Button)"""

    def __init__(self):

        self.enabled = True

        self.checked = False

    def onClick(self):

        #Define the map document and data frame

        mxd = arcpy.mapping.MapDocument("CURRENT")

        df = arcpy.mapping.ListDataFrames(mxd,"*")[0]



        #Call the open dialog

        openValue = pythonaddins.OpenDialog("Open Dialog", False, r"C:\temp", "Open")

        #Make sure dialog was not canceled.

        if openValue != None:

            #Create the layer 

            rasterLayer = arcpy.mapping.Layer(openValue)

            #Add the layer to the map document

            arcpy.mapping.AddLayer(df, rasterLayer,"TOP")

            # Refresh map document

            arcpy.RefreshActiveView()

            arcpy.RefreshTOC()

            del mxd, df, openValue

        else:

            pythonaddins.MessageBox("No data will be added to the map document.", "Warning Message", 0)

del mxd, df, openValue 

【创建及修改时间】
Created: 8/24/2012

Last Modified: 7/10/2013
【原文链接】
http://support.esri.com/en/kno ... 40535