Opening and saving files: an example

This example consists of several scripts that handle opening and saving files. Users can open existing files and save changes. They can also save the contents to another file. If users save the file they opened, saving proceeds without interrupting the user. If users save to a file name that exists, but is not the file they opened, they are asked whether to overwrite the file:

The screen for opening and saving RTF files has three buttons across the top, Open, Save, and Save As. The name of the open file displays below the buttons, and a Modified checkbox indicates whether the file has been changed. The formatting toolbar is next, and below it is the text of the open file.

The example includes instance variable declarations, scripts, functions, and events.

Instance variable declarations

ib_saveas A flag for the FileExists event. When FALSE, the user is saving to the file that was opened, so overwriting is expected:

boolean ib_saveas=FALSE

is_filename The current file name for the contents, initially set to "Untitled":

string is_filename

Open Document script

This script opens a file chosen by the user. Since opening a file triggers the Modified event and sets the Modified property, the script resets Modified to FALSE. The Checked property of the Modified check box is set to FALSE too:

integer li_answer, li_result
string ls_name, ls_path

li_answer = GetFileOpenName("Open File", ls_path, &
   ls_name, "rtf", &
   "Rich Text(*.RTF),*.RTF, Text files(*.TXT),*.TXT")

IF li_answer = 1 THEN
   // User did not cancel
   li_result = rte_1.InsertDocument(ls_path, TRUE)

   IF li_result = 1 THEN  // Document open successful
      // Save and display file name
      is_filename = ls_path
      st_filename.Text = is_filename

      // Save and display modified status   
      rte_1.Modified = FALSE

      cbx_modified.Checked = rte_1.Modified   
   ELSE

      MessageBox("Error", "File not opened.")   
   END IF

   END IF
RETURN 0

Scripts that save the document

The user might choose to save the document to the same name or to a new name. These scripts could be assigned to menu items as well as buttons. The Save button script checks whether the instance variable is_filename holds a valid name. If so, it passes that file name to the of_save function. If not, it triggers the SaveAs button’s script instead:

integer li_result
string ls_name

// If not associated with file, get file name
IF is_filename = "Untitled" THEN
   cb_saveas.EVENT Clicked()

ELSE
   li_result = Parent.of_save(is_filename)
END IF
RETURN 0

The SaveAs script sets the instance variable ib_saveas so that the FileExists event, if triggered, knows to ask about overwriting the file. It calls of_getfilename to prompt for a file name before passing that file name to the of_save function.

integer li_result
string ls_name

ib_saveas = TRUE

ls_name = Parent.of_getfilename()
// If the user canceled or an error occurred, abort
IF ls_name = "" THEN RETURN -1

li_result = Parent.of_save(ls_name)

ib_saveas = FALSE
RETURN 0

Functions for saving and getting a file name

of_save function This function accepts a file name argument and saves the document. It updates the file name instance variable with the new name and sets the check box to correspond with the Modified property, which is automatically set to FALSE after you call SaveDocument successfully:

integer li_result

MessageBox("File name", as_name)

// Don't need a file type because the extension
// will trigger the correct type of save
li_result = rte_1.SaveDocument(as_name)

IF li_result = -1 THEN
   MessageBox("Warning", "File not saved.")
   RETURN -1
ELSE
   // File saved successfully
   is_filename = as_name
   st_filename.Text = is_filename
   cbx_modified.Checked = rte_1.Modified
   RETURN 1
END IF

of_getfilename function The function prompts the user for a name and returns the file name the user selects. It is called when a file name has not yet been specified or when the user chooses Save As. It returns a file name:

integer li_answer
string ls_name, ls_path

li_answer = GetFileSaveName("Document Name", ls_path, &
   ls_name, "rtf", &
   "Rich Text(*.RTF),*.RTF,Text files(*.TXT),*.TXT")

IF li_answer = 1 THEN
   // Return specified file name
   RETURN ls_path
ELSE
   RETURN ""
END IF

Events for saving and closing

FileExists event When the user has selected a file name and the file already exists, this script warns the user and allows the save to be canceled. The event occurs when SaveDocument tries to save a file and it already exists. The script checks whether ib_saveas is TRUE and, if so, asks if the user wants to proceed with overwriting the existing file:

integer li_answer

// If user asked to Save to same file,
// don't prompt for overwriting
IF ib_saveas = FALSE THEN RETURN 0

li_answer = MessageBox("FileExists", &
   filename + " already exists. Overwrite?", &
   Exclamation!, YesNo!)

// Returning a non-zero value cancels save
IF li_answer = 2 THEN RETURN 1

Modified event This script sets a check box so the user can see that changes have not been saved. The Modified property is set automatically when the event occurs. The event is triggered when the first change is made to the contents of the control:

cbx_modified.Checked = TRUE

CloseQuery event This script for the window’s CloseQuery event checks whether the control has unsaved changes and asks whether to save the document before the window closes:

integer li_answer

// Are there unsaved changes? No, then return.
IF rte_1.Modified = FALSE THEN RETURN 0

// Ask user whether to save
li_answer = MessageBox("Document not saved", &
   "Do you want to save " + is_filename + "?", &
   Exclamation!, YesNo! )

IF li_answer = 1 THEN
   // User says save. Trigger Save button script.
   cb_save.EVENT Clicked()
END IF
RETURN 0