Using the <i class="emphasis">OpenFileDialog</i> Class

Using the OpenFileDialog Class

As discussed in the In Depth section of this chapter, Open File dialogs let you get the name or names of files to open from the user. They're based on the OpenFileDialog class, which has this class hierarchy:

Object
   MarshalByRefObject
      Component
         CommonDialog
            FileDialog
               OpenFileDialog

You can find the notable public properties of OpenFileDialog objects in Table 9.9, the notable public methods in Table 9.10, and the notable public events in Table 9.11.

Table 9.9: Noteworthy public properties of *OpenFileDialog* objects.
Property	Means
AddExtension	Gets/sets if the dialog box adds an extension to file names if the user doesn't supply the extension.
CheckFileExists	Gets/sets if the dialog box displays a warning if the user specifies a nonexistent file.
CheckPathExists	Gets/sets whether the dialog box displays a warning if the user gives a path that does not exist.
DefaultExt	Gets/sets the default file extension.
FileName	Gets/sets the file name selected in the file dialog box.
FileNames	Gets the file names of all selected files.
Filter	Gets/sets the current file name filter string, which sets the choices that appear in the "Save as file type" or "Files of type" box.
FilterIndex	Gets/sets the index of the filter selected in the file dialog box.
InitialDirectory	Gets/sets the initial directory used in the file dialog box.
Multiselect	Gets/sets whether the dialog box allows multiple file selections.
ReadOnlyChecked	Gets/sets whether the read-only checkbox is checked.
RestoreDirectory	Gets/sets whether the dialog box should restore the original directory before closing.
ShowHelp	Gets/sets whether the Help button should be displayed.
ShowReadOnly	Gets/sets whether the dialog displays a read-only check box.
Title	Gets/sets the file dialog box title.
ValidateNames	Gets/sets a value specifying if the dialog box accepts only valid (that is, Win32) file names.

Table 9.10: Noteworthy public methods of *OpenFileDialog* objects.
Method	Means
OpenFile	Opens the file selected by the user, with read-only permission. The file is specified by the FileName property.
Reset	Resets all options to their default values.
ShowDialog	Shows the dialog box.

Table 9.11: Noteworthy public events of *OpenFileDialog* objects.
Event	Means
FileOk	Occurs when the user clicks the Open or Save button.
HelpRequest	Occurs when the user clicks the Help button.