How to use Worksheets.PrintPreview in the xlwings API way

The PrintPreview method in the Worksheets object is a powerful feature in Excel’s object model that allows users to preview how a worksheet will appear when printed, without actually sending it to the printer. This functionality is essential for ensuring proper formatting, layout, and page breaks before finalizing print jobs, saving both time and resources. In xlwings, a Python library that automates Excel through its COM interface, accessing this method enables seamless integration of print preview capabilities into automated scripts or applications.

Functionality:
The PrintPreview method displays the print preview dialog for a specified worksheet, showing a visual representation of the printed pages. It helps users check margins, headers, footers, scaling options, and overall page arrangement. This is particularly useful in automated reporting workflows where multiple worksheets are generated programmatically, and manual verification of each sheet’s print layout would be inefficient.

Syntax in xlwings:
In xlwings, the PrintPreview method is accessed through a Worksheet object, which is part of the Worksheets collection. The general syntax is as follows:

worksheet.api.PrintPreview()

Here, worksheet refers to an xlwings Worksheet object representing the target sheet. The .api attribute provides direct access to the underlying Excel object model (via pywin32 on Windows or appscript on macOS), allowing calls to native methods like PrintPreview. This method does not require any parameters, as it simply activates the print preview interface for the active worksheet context.

Key Considerations:

• The PrintPreview method is a member of the Excel Worksheet object, not the Worksheets collection itself. Thus, you must call it on a specific worksheet instance.
• In xlwings, the method is invoked via the .api property to bridge Python with Excel’s COM automation. Without this, xlwings’ high-level API does not directly expose PrintPreview.
• The method opens Excel’s print preview window, which is modal by default—meaning the script will pause until the user closes the preview. To avoid interruptions in automation, consider alternative approaches like setting print properties programmatically.

Code Examples:
Below are practical examples demonstrating the use of PrintPreview with xlwings in different scenarios.

Example 1: Basic Print Preview for an Active Worksheet
This code opens an Excel workbook and triggers the print preview for the first worksheet.

import xlwings as xw

# Open an existing workbook or create a new one
wb = xw.Book('example.xlsx')
ws = wb.sheets[0] # Access the first worksheet

# Activate print preview
ws.api.PrintPreview()

Example 2: Preview Multiple Worksheets in a Loop
This script iterates through all worksheets in a workbook and opens print preview for each, allowing batch inspection.

import xlwings as xw

wb = xw.Book('report.xlsx')
for sheet in wb.sheets:
    print(f"Previewing: {sheet.name}")
    sheet.api.PrintPreview()
    # Note: The script waits for user to close each preview window

Example 3: Conditional Print Preview Based on Content
Here, print preview is only triggered for worksheets that contain data beyond a certain threshold, optimizing the workflow.

import xlwings as xw

wb = xw.Book('data.xlsx')
for ws in wb.sheets:
    # Check if the worksheet has more than 10 used rows
    if ws.used_range.last_cell.row > 10:
        print(f"Previewing large sheet: {ws.name}")
        ws.api.PrintPreview()