A strange error with system data

Microsoft.Office.Interop.Word and System.Data are both namespaces in .NET, and when you introduce an alias (in this case, Word) for Microsoft.Office.Interop.Word, it can cause naming conflicts in the code. The C# compiler might become confused about which Data you are referring to, leading to the observed behavior.

 

Use Fully Qualified Names: Instead of using an alias for Microsoft.Office.Interop.Word, you can use fully qualified names when working with classes from this namespace. For example:

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

By using the fully qualified name, you avoid namespace conflicts.

Check Your Using Statements Order: Make sure that your using statements are properly ordered at the top of your file. Namespaces should be imported in a way that avoids conflicts. For example, you should place using System.Data and other standard .NET namespaces before any custom or third-party namespaces.

Separate Code Files: If you're working in separate forms, ensure that each form's code is in a separate code file. This separation can help avoid naming conflicts, especially if you have different using statements in each file.

Namespace Renaming: If you find that using fully qualified names or rearranging using statements doesn't resolve the issue, you might consider renaming your custom alias for Microsoft.Office.Interop.Word to something less likely to conflict with other namespaces. For example:

using WordInterop = Microsoft.Office.Interop.Word;

This way, you can use WordInterop without causing a conflict with System.Data.