Tuto WINDEV 25

170 Part 4: Full application with data In these different codes: • HReadLast is used to read the last file record according to the key used for the last search. • HReadNext reads the record whose key value is immediately greater than the one of current record. • HReadPrevious reads the record whose key value is immediately less than the one of current record. In any case: • HOut is used to find out whether the data file is empty. • FileToScreen is used to display the record on the screen. Remark The code in the "Next" and "Previous" Button controls contains additional lines of code to: • Check whether a search was already performed in the Customer data file (test of HOut to find out whether the file reading has started). • Read the first or last record if necessary. Indeed, the next or previous record cannot be read if no reading was performed in the data file. ▶ Save the window by clicking among the quick access buttons. Window test ▶ Let’s run a window test: 1. Run the window test ( among the quick access buttons). 2. Click the "Finding customers" tab pane if necessary. 3. Find a customer (perform a generic search on "BEEF" for example). 4. Browse the data file by clicking each one of the browse buttons. 5. Stop the test to go back to the editor.