Why Are My C# Database Updates Not Saving in Visual Studio?

Debugging C# Database Update Save Failures

Using C# to update databases can lead to frustrating situations where changes aren't saved. A common culprit is the |DataDirectory| placeholder in your connection string.

Understanding the |DataDirectory| Placeholder

|DataDirectory| specifies the database file's location. During Visual Studio debugging, it points to the project's BINDEBUG folder (or the x86 equivalent). Updates work here.

The Visual Studio Server Explorer Discrepancy

However, Visual Studio's Server Explorer (and other database tools) often use a different connection string, pointing to the database in your project folder. Changes made during debugging won't appear in Server Explorer until you manually refresh or create a new connection.

Visual Studio's Automatic Database Copying

If your database file is in your project, and "Copy to Output Directory" is set to "Copy Always," Visual Studio copies it to BINDEBUG, overwriting any changes made during debugging.

Solutions

To fix this:

1. Change the database file's "Copy to Output Directory" property in Solution Explorer to "Copy if Newer" or "Never Copy."
2. Alternatively, update Server Explorer's connection string to point to the BINDEBUG database copy.

Best Practice: Dual Connections

Create two Server Explorer connections: one to the project folder's database (for schema changes and deployment), and another to the BINDEBUG copy (to see your code's effects).

MS Access Databases: A Special Note

With MS Access, even viewing a table changes its modified date, triggering "Copy if Newer." Use "Never Copy" for MS Access databases.

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