Tk4.2 User Commands Man Page -- getOpenFile (n)

NAME

tk_getOpenFile, tk_getSaveFile - pop up a dialog box for the user to select a file to open or save.

SYNOPSIS

tk_getOpenFile ?option value ...?

tk_getSaveFile ?option value ...?

The procedures tk_getOpenFile and tk_getSaveFile pop up a dialog box for the user to select a file to open or save. The tk_getOpenFile command is usually associated with the "Open" command in the "File" menu. Its purpose is for the user to select an existing file only. If the user enters an non-existent file, the dialog box gives the user an error prompt and requires the user to give an alternative selection. If an application allows the user to create new files, it should do so by providing a separate "New" menu command.

The tk_getSaveFile command is usually associated with the "Save as" command in the "File" menu. If the user enters a file that already exists, the dialog box prompts the user for confirmation whether the existing file should be overwritten or not.

The following option-value pairs are possible as command line arguments to these two commands:

-defaultextension extension: Specifies a string which will be appended to the filename if the user enters a filename without an extension. The defaut value is the empty string, which means no extensions will be appended to the filename in any case. This option is ignored on the Machintosh platform, which does not require extensions to filenames.

-filetypes filePatternList: If a "File types" listbox exists in the file dialog on the particular platform, this option gives the file_types in this listbox. When the user choose a filetype in the listbox, only the files of that type are listed. If this option is unspecified, or if it is set to the empty list, or if the "File types" listbox is not supported by the particular platform then all files are listed regardless of their types. See the section "SPECIFYING FILE PATTERNS" below for a discussion on the contents of filePatternList.

-initialdir directory: Specifies that the files in directory should be displayed when the dialog pops up. If this parameter is not specified, then the files in the current working directory are displayed.

-initialfile filename: Specifies a filename to be displayed in the dialog when it pops up. This option is ignored by the tk_getOpenFile command.

-parent window: Makes window the logical parent of the file dialog. The file dialog is displayed on top of its parent window.

-title titleString: Specifies a string to display as the title of the dialog box. If this option is not specified, then a default title is displayed. This option is ignored on the Machintosh platform.

If the user selects a file, both tk_getOpenFile and tk_getSaveFile return the full pathname of this file. If the user cancels the operation, both commands return the empty string.

SPECIFYING FILE PATTERNS

The filePatternList value given by the -filetypes option is a list of filePatterns. Each filePattern is a list of the form
typeName {extension ?extension ...?} ?{macType ?macType ...?}? typeName is the name of the filetype described by this filePattern and is the text string that appears in the "File types" listbox. extension is a file extension for this filePattern. macType is a four-character Machintosh file type. The list of macTypes is optional and may be omitted for applications that do not need to execute on the Machintosh platform.

Several filePatterns may have the same typeName, in which case they refer to the same file type and share the same entry in the listbox. When the user selects an entry in the listbox, all the files that matches with at leat one of the filePatterns corresponding to that entry are listed. Usually, each filePattern corresponds to an distinct type of file. The use of more than one filePatterns for one type of file is necessary on the Machintosh platform only.

On the Machintosh platform, a file matches with a filePattern if its name matches with at least one of the extension(s) AND it belongs to at least one of the macType(s) of the filePattern. For example, the C Source Files filePattern in the sample code matches with files that have a .c extension AND belong to the macType TEXT. To use the OR rule instead, you can use two filePatterns, one with the extensions only and the other with the macType only. The GIF Files file type in the sample code matches with files that EITHER have a .gif extension OR belong to the macType GIFF.

On the Unix and Windows platforms, a file matches with a filePattern if its name matches with at at least one of the extension(s) of the filePattern. The macTypes are ignored.

SPECIFYING EXTENSIONS

On the Unix and Machintosh platforms, extensions are matched using glob-style pattern matching. On the Windows platforms, extensions are matched by the underlying operating system. The types of possible extensions are: (1) the special extension * matches with any file; (2) the special extension "" matches with any files that do not have an extension (i.e., the filename contains no full stop character); (3) any character string that does not contain any wild card characters (* and ?).

Due to the different pattern matching rules on the various platforms, to ensure portability, wild card characters are not allowed in the extensions, except as in the special extension *. Extensions without a full stop character (e.g, ~) are allowed but may not work on all platforms.

EXAMPLE

set types {

{"Text Files": {.txt} } {"TCL Scripts" {.tcl} } {"C Source Files" {.c} TEXT}

{"GIF Files": {.gif} }

{"GIF Files": {} GIFF} {"All Files" * } } set filename [tk_getOpenFile -filetypes $types]

if {$filename != ""} {
# Open the file ...
}

KEYWORDS

file selection dialog

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