Method invocation failed because [System.__ComObject] does not contain a method named 'Close' in Powershell v4.0

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07-10-2024

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"Method invocation failed because [System.__ComObject] does not contain a method named 'Close'" Error in PowerShell v4.0: Understanding and Solutions

Scenario: You're using PowerShell v4.0 to interact with a COM object (Component Object Model), but you encounter the error "Method invocation failed because [System.__ComObject] does not contain a method named 'Close'." This error signifies that the COM object you're working with lacks a "Close" method, despite your script attempting to call it.

Example:

$excel = New-Object -ComObject Excel.Application
$excel.Visible = $true

# Your code that uses the Excel object

$excel.Close()  # This line throws the error

Understanding the Issue:

The error arises because COM objects, particularly those from older applications like Microsoft Excel, may not have a standard "Close" method. The PowerShell script is attempting to close the Excel application using a conventional method, which is not implemented.

Solutions:

1. Utilize Object-Specific Methods: Explore alternative methods provided by the COM object. In the Excel example, you might use the Quit() method:

   $excel.Quit()
   

2. Release the Object: Release the object from memory using the $null assignment:

   $excel = $null
   

   While this doesn't explicitly close the application, it releases the object's reference, allowing it to be garbage collected.

3. Use the ReleaseComObject Function: PowerShell provides the ReleaseComObject function to explicitly release COM objects:

   [System.Runtime.InteropServices.Marshal]::ReleaseComObject($excel)
   

   This ensures the object is properly released, reducing the risk of memory leaks.

4. Directly Close the Application: For specific cases, you might have to resort to closing the application directly. You can achieve this using the System.Diagnostics.Process class:

   $excelProcess = Get-Process -Name EXCEL 
   $excelProcess.CloseMainWindow()
   $excelProcess.WaitForExit()
   

   This approach closes the Excel window and waits for the process to terminate.

Best Practices:

• Always refer to the documentation of the specific COM object you're working with to identify appropriate methods for closing or releasing it.
• Implement a consistent approach for releasing COM objects in your scripts to avoid potential issues.
• Consider using the ReleaseComObject function for a more controlled and robust method of releasing COM objects.

Additional Resources:

• Microsoft Docs - ReleaseComObject
• Microsoft Docs - Working with COM Objects

Conclusion:

The "Method invocation failed" error in PowerShell v4.0 can be frustrating, but understanding the underlying issue and implementing the appropriate solutions helps maintain script stability and efficient resource management. By following best practices and leveraging the tools provided by PowerShell, you can effectively manage COM objects and avoid encountering this common error.