Merge pull request #2544 from PySimpleGUI/Dev-latest

New Demo showing using invisble input elements as target

DemoPrograms/Demo_Button_Events_From_Browse.py

@@ -0,0 +1,32 @@
+import PySimpleGUI as sg
+
+"""
+    Demo - Fill a listbox with list of files FilesBrowse button
+
+    This technique can be used to generate events from "Chooser Buttons" like FileBrowse, FilesBrowse
+    FolderBrowser, ColorChooserButton, Calendar Button
+
+    Any button that uses a "Target" can be used with an invisible Input Element to generate an
+    event when the user has made a choice.  Enable events for the invisible element and an event will
+    be generated when the Chooser Button fills in the element
+
+    This particular demo users a list of chosen files to populate a listbox
+
+
+"""
+
+
+layout = [  [sg.LBox([], size=(20,10), key='-FILESLB-')],
+            [sg.Input(visible=False, enable_events=True, key='-IN-'), sg.FilesBrowse()],
+            [sg.Button('Go'), sg.Button('Exit')]  ]
+
+window = sg.Window('Window Title', layout)
+
+while True:             # Event Loop
+    event, values = window.read()
+    if event in (None, 'Exit'):
+        break
+    # When choice has been made, then fill in the listbox with the choices
+    if event == '-IN-':
+        window['-FILESLB-'].Update(values['-IN-'].split(';'))
+window.close()