Combo

(Extends the OptionMenu class from tkinter)

Purpose

Display a drop down box allowing an option to be selected from a list of options

class guizero.Combo(master, options, selected=None, command=None, grid=None, align=None)

Create a Combo object

Create a basic Combo object like this:

from guizero import App, Combo
app = App()
combo = Combo(app, options=["Beef", "Chicken", "Fish", "Vegetarian"])
app.display()

The options parameter should be a list of options you wish to display in the combo box. All options will be converted to strings when added to the Combo box.

The above code looks like this on Windows:

When creating a Combo object, you can specify the following parameters. (More information about how to specify parameters can be found in the 'How to...' section.)

Parameter	Takes	Default	Compulsory	Description
master	App or Box	-	Yes	The container to which this widget belongs
options	List	-	Yes	A list of options to display
command	function name	None	No	The name of a function to call when a different option is selected. The command can only be specified when creating the Combo object and cannot be changed later.
grid	List [int, int]	None	No	[x,y] coordinates of this widget. This parameter is only required if the master object has a grid layout.
align	string	None	No	Alignment of this widget within its grid location. Possible values: "top", "bottom", "left", "right". This parameter is only required if the master object has a grid layout.

Methods

You can call the following methods on your Combo object

Method	Takes	Returns	Description
get()	-	string	Returns the currently selected option
set(text)	text (string)	-	Sets the currently selected option to the option matching the string text
select_default()	-	-	Resets the combo box so that the first item in the list is selected
add_option(option)	option (string)	-	Adds a new item to the combo box with the value option
clear()	-	-	Removes all options from the Combo box

Examples

Creating a Combo

The simplest way to create a Combo object is as follows:

from guizero import App, Combo
app = App()
combo = Combo(app, options=["Beef", "Chicken", "Fish", "Vegetarian"])
app.display()

Calling a function when the value selected changes

You can call a function when the selected value in a Combo object changes. This must be set up at the time you create the Combo object and cannot be defined later. The function you call MUST take a minimum of one parameter as it will automatically be passed a string containing the currently selected value in the Combo object.

from guizero import App, Text, Combo
def you_chose(selected_value):
    result.set("You chose...")
    if selected_value == "Tiny goblet":
        result.append("wisely")
    else:
        result.append("poorly")

app = App()
instructions = Text(app, text="Choose a goblet")
combo = Combo(app, options=["", "Huge golden goblet", "Jewel encrusted goblet", "Tiny goblet"], command=you_chose)
result = Text(app)
app.display()