ADO.NET |DataDirectory| where is this documented?

Question

In AppConfig it is possible to use |DataDirectory| but I can\'t find any doc ?

Answer 1

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|DataDirectory| (enclosed in pipe symbols) is a substitution string that indicates the path to the database. It eliminates the need to hard-code the full path which leads to several problems as the full path to the database could be serialized in different places. DataDirectory also makes it easy to share a project and also to deploy an application.

For example, instead of having the following connection string:

"Data Source= c:\program files\MyApp\Mydb.sdf"

Using DataDirectory, you can have the following connection string:

“Data Source = |DataDirectory|\Mydb.sdf”

To set the DataDirectory property, call the AppDomain.SetData method. If you do not set the DataDirectory property, the following default rules will be applied to access the database folder:

• For applications that are put in a folder on the user's computer, the database folder uses the application folder.
• For applications that are running under ClickOnce, the database folder uses the specific data folder that is created.