How to use Application.COMAddIns in the xlwings API way

The Application.COMAddIns property in Excel’s object model provides access to the collection of currently installed COM add-ins. This is particularly useful for developers who need to programmatically check, manage, or interact with these add-ins from within Python using the xlwings library. COM add-ins extend Excel’s functionality, and accessing them via xlwings allows for automation tasks such as verifying if a specific add-in is loaded, enabling or disabling add-ins, or retrieving details about them.

Functionality:
The COMAddIns collection enables you to:

• Count the number of installed COM add-ins.
• Iterate through each COM add-in to get its ProgID (Programmatic Identifier), description, and connection state (whether it is loaded or not).
• Activate or deactivate an add-in programmatically.
• This is essential for ensuring that dependent add-ins are available before executing macros or functions that rely on them, improving script robustness.

Syntax in xlwings:
In xlwings, you access this property through the api property of the App or Application object. The typical call format is:

app = xw.App() # or xw.apps.active for an existing instance
com_addins = app.api.COMAddIns

Once you have the collection, you can use its methods and properties. Key members include:

• Count: Returns the number of COM add-ins (integer).
• Item(index): Retrieves a specific COMAddIn object, where index can be an integer (1-based) or the add-in’s ProgID (string).
• Update(): Updates the list of COM add-ins from the registry.

For a COMAddIn object, important properties are:

• ProgId: The programmatic identifier (string).
• Description: A descriptive name (string).
• Connect: A boolean indicating if the add-in is currently loaded (True/False). Setting this property enables or disables the add-in.

Example Usage:
Below is a practical xlwings code example that demonstrates how to list all COM add-ins and toggle one add-in’s state:

import xlwings as xw

# Connect to the active Excel instance
app = xw.apps.active

# Access the COMAddIns collection
com_addins = app.api.COMAddIns

# Print the number of add-ins
print(f"Total COM add-ins: {com_addins.Count}")

# Iterate through each add-in and display details
for i in range(1, com_addins.Count + 1):
    addin = com_addins.Item(i)
    print(f"Add-in {i}:")
    print(f" ProgID: {addin.ProgId}")
    print(f" Description: {addin.Description}")
    print(f" Loaded: {addin.Connect}")

# Example: Toggle the state of a specific add-in by ProgID
target_progid = "Example.AddIn" # Replace with an actual ProgID
try:
    specific_addin = com_addins.Item(target_progid)
    current_state = specific_addin.Connect
    specific_addin.Connect = not current_state # Toggle the state
    print(f"Toggled add-in '{target_progid}' from {current_state} to {specific_addin.Connect}")
except Exception as e:
    print(f"Add-in '{target_progid}' not found or error: {e}")

# Optional: Update the collection
com_addins.Update()