Creating Pop-up Windows

Midware Ltd.

Sometimes it's convenient to display a pop-up window in a display file rather than displaying a whole new screen. For example, you may want to have a confirmation message "Are you really sure? (Y/N)" or display summary totals for a list.

It's easy to code this in your display file DDS. Create a new record with a type of WINDOW rather than RECORD. You can also create a type of WDWSFL to create a window subfile.

You must include the dimensions of the window in rows and columns. You can optionally specify a position for the window to be displayed. If you do not specify a position, the system will automatically determine an appropriate starting position based on the size of the window and the position of the cursor.

WINDOW(2 2 10 50)

The previous statement will define a window 10-rows by 50-columns, displayed starting in row 2, column 2.

You can also explicitly code the WDWBORDER keyword to specify a border for the window. Often, a combination of "." and ":" is used to create a border. However, if you leave this parameter blank, a default border will be used that looks much cleaner.

A window or window subfile function exactly like a normal record or record subfile from the program's perspective. The only difference is how the screen is displayed.

Overlaying the window(s)

Unfortunately, windows don't automatically overlay the screen behind them - even with the OVERLAY keyword. Instead, the only way I've found to get the desired results (and I don't know why this is) is to:

Set up a dummy record in your display file. You can call it anything you want. Your program doesn't even need to reference it! I normally name it "KA".
Code a literal on the dummy record. It could be a simple as a space in one of the corners.
Code the record with the KEEP and ASSUME keywords.

Any windows displayed now (even from a called programs) will automatically overlay whatever screen is currently displayed.

Last Modified: September 25, 2000