How to use Worksheets.Application in the xlwings API way

The Application member of the Worksheets object in Excel’s object model provides a bridge to the overarching Excel application instance from a specific worksheets collection. In xlwings, this is accessed via the api property, which exposes the underlying COM object, allowing you to leverage Excel’s native object model directly. This is particularly useful for retrieving high-level application settings, controlling Excel’s behavior, or accessing other top-level objects that aren’t directly exposed through xlwings’ simplified object model.

Functionality:
The primary purpose of accessing Application through a Worksheets object is to obtain a reference to the Excel Application object. This reference enables you to:

• Retrieve application-wide properties (e.g., Application.Version, Application.ScreenUpdating).
• Execute application-level methods (e.g., Application.Calculate, Application.Quit).
• Access other collections like Workbooks, Windows, or AddIns.

Syntax in xlwings:
The general syntax to access the Application member via xlwings is:

ws_object.api.Application

Where ws_object is an xlwings Sheets or Worksheet object. From this, you can chain to properties or methods of the Excel Application object.

Common Properties and Methods via Application:

• Properties:
• .Version: Returns the Excel version as a string.
• .ScreenUpdating: Gets or sets a Boolean to control screen refresh.
• .DisplayAlerts: Gets or sets a Boolean to control alert displays.
• .Calculation: Gets or sets the calculation mode (e.g., xlCalculationAutomatic, xlCalculationManual). Use xlwings constants like xlwings.constants.xlCalculationAutomatic.
• Methods:
• .Calculate(): Forces a recalculation of all open workbooks.
• .Quit(): Closes the Excel application. Use with caution.

Code Examples:

1. Retrieving Excel Application Version and Controlling Screen Updates:

import xlwings as xw

# Connect to an existing workbook or create a new one
wb = xw.Book() # Opens a new workbook
ws = wb.sheets[0] # Get the first worksheet

# Access Application via the worksheet
app = ws.api.Application

# Get Excel version
print(f"Excel Version: {app.Version}")

# Turn off screen updating for performance
app.ScreenUpdating = False

# Perform some operations (e.g., writing data)
ws.range('A1').value = 'Hello, World!'
wb.save('test.xlsx')

# Turn screen updating back on
app.ScreenUpdating = True

2. Changing Calculation Mode and Forcing Recalculation:

import xlwings as xw
from xlwings.constants import Calculation

wb = xw.Book('example.xlsx')
ws = wb.sheets['Data']

app = ws.api.Application

# Set calculation to manual
app.Calculation = Calculation.xlCalculationManual
print("Calculation mode set to manual.")

# After making changes to formulas, force a full calculation
app.Calculate()
print("Forced recalculation performed.")

# Revert to automatic calculation
app.Calculation = Calculation.xlCalculationAutomatic

3. Accessing Other Application-Level Collections:

import xlwings as xw

wb = xw.Book()
ws = wb.sheets[0]

app = ws.api.Application

# List all open workbooks via Application
for wb in app.Workbooks:
    print(wb.Name)

# Check if alerts are displayed
if app.DisplayAlerts:
    print("Alerts are enabled.")