AllowAddNew | Hackers Guide to Visual FoxPro 7.0

CursorSource, Database

These two properties belong to cursors in the DataEnvironment. They determine what table or view the cursor references. CursorSource contains some version of the name of the table or view—the name used depends on whether it's a table or view and, for tables, whether it's free or contained in a database. (See Help for the details.) Database contains the full path to the database containing the table or view, if the cursor isn't a free table.

Usage

curCursor.CursorSource = cName cName = curCursor.CursorSource curCursor.Database = cFullyPathedFileName cFullyPathedFileName = curCursor.Database

Being able to change these properties, especially Database, at runtime is important. By changing Database, you can change a form from using last year's data to this year's, or from using one client's to another's, or from using local data to remote. Changing CursorSource seems less common to us.

You can make these changes in the DataEnvironment's OpenTables method. To our pleasant surprise, although the objects involved haven't been Init-ed yet, the changes stick and do affect the initial automatic opening of tables. Keep in mind that doing it in OpenTables means it'll happen every time you call that method.

Don't change these while the tables are open—you'll get an error. Instead, call CloseTables to close them, make the changes, and then call OpenTables to reopen them.

If you want to choose a database based on a parameter to the form, you can't use all of the automatic table-opening features of the form. That's because OpenTables occurs before all other events (even Form.Load and more importantly, Form.Init, which receives parameters), when AutoOpenTables is .T. In this case, you can set AutoOpenTables to .F., and, in the form's Init, set Database for each cursor (think SetAll), then call OpenTables. Unfortunately, this means you can't bind controls to the table data at design-time. You may want to consider using a "global" property, such as oApp.cDataDirectory, to point to the data. Then you can set the Database property of cursors in the form's Load.

Example

* Point a cursor to the already open and current database. ThisForm.DataEnvironment.curCustomer.Database = DBC()