How can I show only certain file extensions in an open-file dialog?

Question

When I open a folder with an OpenDialog, how can I filter it so users can view only certain files (e.g., Stringgrid, *.sg) and the files with any other extension do not appear in the dialog window?

Answer 1

Set the OpenDialog.Filter property to the file filter you want.

You can do this in the Object Inspector:

• Click in the Filter property, and you'll see a small button appear on the right edge with ....
• Click that, and you'll see a dialog appear.

On the left side is the description of the file (for instance, Excel files (*.xls)). The right side is the filter you want to use, as in *.xls.

You can also set it in code before displaying your dialog:

OpenDialog1.Filter := 'Excel files (*.xls)|*.xls';

Of course, replace the Excel stuff with any description and mask you want to use.

Answer 2

The Filter and FilterIndex properties are used to specify which file extension(s) to display (note that the user can override the filter manually, though).

The OnIncludeItem event is used to selectively allow/disallow individual files/folders from being listed in the dialog.