Issue with Microsoft.Office.Interop.Word in ASP.NET Project

Question

I am currently working on an ASP.NET project using Visual Studio and have installed Office 365 on our system. I have added a reference to Microsoft.Office.Interop.Word in the project via NuGet Package Manager, intending to automate Microsoft Word functionalities within my application.

However, I am encountering the following error when attempting to create a Word.Application instance:

 

Error Details:

System.InvalidCastException: 'Unable to cast COM object of type 'Microsoft.Office.Interop.Word.ApplicationClass' to interface type 'Microsoft.Office.Interop.Word._Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00020970-0000-0000-C000-000000000046}' failed due to the following error: Element not found. (Exception from HRESULT: 0x8002802B (TYPE_E_ELEMENTNOTFOUND)).'

 

Steps to Reproduce:

1. Installed Office 365 on the system.
2. Created an ASP.NET project in Visual Studio.
3. Added a reference to Microsoft.Office.Interop.Word using the NuGet Package Manager.
4. Attempted to initialize a Word application using the code:

 

var wordApp = new Microsoft.Office.Interop.Word.Application();

 

Additional Notes:

• I have checked that Office 365 is correctly installed and licensed.
• The project targets .NET Framework.
• Running Visual Studio as an administrator does not resolve the issue.

 

Question: Can Microsoft.Office.Interop.Word be used in an ASP.NET project when Office 365 is installed? If so, could you please provide guidance on resolving this error?

 

Thank you for your assistance.I am currently working on an ASP.NET project using Visual Studio and have installed Office 365 on our system. I have added a reference to Microsoft.Office.Interop.Word in the project via NuGet Package Manager, intending to automate Microsoft Word functionalities within my application.

However, I am encountering the following error when attempting to create a Word.Application instance:

 

Error Details:

System.InvalidCastException: 'Unable to cast COM object of type 'Microsoft.Office.Interop.Word.ApplicationClass' to interface type 'Microsoft.Office.Interop.Word._Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00020970-0000-0000-C000-000000000046}' failed due to the following error: Element not found. (Exception from HRESULT: 0x8002802B (TYPE_E_ELEMENTNOTFOUND)).'

 

Steps to Reproduce:

1. Installed Office 365 on the system.
2. Created an ASP.NET project in Visual Studio.
3. Added a reference to Microsoft.Office.Interop.Word using the NuGet Package Manager.
4. Attempted to initialize a Word application using the code:

 

var wordApp = new Microsoft.Office.Interop.Word.Application();

 

Additional Notes:

• I have checked that Office 365 is correctly installed and licensed.
• The project targets .NET Framework.
• Running Visual Studio as an administrator does not resolve the issue.

 

Question: Can Microsoft.Office.Interop.Word be used in an ASP.NET project when Office 365 is installed? If so, could you please provide guidance on resolving this error?

 

Thank you for your assistance.

Answer 1

System.InvalidCastException: 'Unable to cast COM object of type 'Microsoft.Office.Interop.Word.ApplicationClass' to interface type 'Microsoft.Office.Interop.Word._Application', typically occurs when there is an issue with the COM component registration or the Office Interop assemblies.

 

1.      Ensure Office is Properly Installed: Make sure that Microsoft Office is correctly installed on your system. Sometimes, reinstalling Office can resolve issues related to COM components.

2.      Check for Correct Version of Interop Assemblies: Verify that you are using the correct version of the Microsoft.Office.Interop.Word assemblies. You can do this by checking the references in your project and ensuring they match the version of Office installed on your system.

3.      Register the COM Component: You might need to manually register the COM component. Open a command prompt with administrative privileges and run the following command:

Replace OfficeXX with the appropriate version number of your Office installation.

4.      Check for Missing or Corrupt Files: Sometimes, missing or corrupt files can cause this error. Running a repair on your Office installation can help fix these issues.

5.      Update Your System: Ensure that your Windows operating system and Office applications are up to date with the latest patches and updates.

You can use Microsoft.Office.Interop.Word in an ASP.NET project even when Office 365 is installed. However, there are some considerations and steps you need to follow to resolve the error you're encountering.

The error System.InvalidCastException: 'Unable to cast COM object of type 'Microsoft.Office.Interop.Word.ApplicationClass' to interface type 'Microsoft.Office.Interop.Word._Application' typically occurs due to issues with the COM component registration or the Office Interop assemblies. Here are some steps to help you resolve this issue:

1.      Ensure Office is Properly Installed: Make sure that Microsoft Office is correctly installed on your system. Sometimes, reinstalling Office can resolve issues related to COM components.

2.      Check for Correct Version of Interop Assemblies: Verify that you are using the correct version of the Microsoft.Office.Interop.Word assemblies. You can do this by checking the references in your project and ensuring they match the version of Office installed on your system.

3.      Register the COM Component: You might need to manually register the COM component. Open a command prompt with administrative privileges and run the following command:

Replace OfficeXX with the appropriate version number of your Office installation.

4. Check for Missing or Corrupt Files: Sometimes, missing or corrupt files can cause   this error.  Running a repair on your Office installation can help fix these issues.

5__.__Update Your System: Ensure that your Windows operating system and Office applications are up to date with the latest patches and updates.

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