The new menu structure for the MyPhotos application

It is tempting to use our own terminology and establish our own conventions here. For example, why not use an “Album” main menu instead of the File menu, or have Ctrl+N as the shortcut for View-Next rather than File-New. The short answer: don’t do it. Computer users appreciate familiarity and resist change (so do most consumers and small children, but I digress). The File menu is standard in most Windows applications, and Ctrl+N is used for creating a new object (be it a document in Microsoft Word, or an image in Adobe PhotoDeluxe). Unless you are intending your application to be somewhat contrary, use existing standards where possible.

So even though Ctrl+N and Ctrl+P would make nice shortcuts for Next and Previous, we will stick with Ctrl+N for New and save Ctrl+P for when we add printing in part 3 of the book. We have already looked at menus in chapter 3, so this section will remove the existing Load menu and add our new menu structure.

Set the version number of the MyPhotos application to 6.1.

REMOVE THE LOAD MENU

The creation of our menu requires the procedures we saw in chapter 3. The following table creates and positions the new menu items required in our application. The subsequent sections will look at the required event handlers for these menu items.

CREATE OUR NEW MENU

CREATE OUR NEW MENU (continued)

The source code generated here does not use anything we have not already seen and discussed in chapter 3, so we will move right along and start processing our new menus.

6.1.2ADDING CLASS VARIABLES

Before we can implement any event handlers for our menus, and in particular before

we can open and save album files, we must have a PhotoAlbum at our disposal in the MainForm class. In chapter 5 we added a reference to the MyPhotoAlbum library in the MyPhotos project, so this library is already available to our application.

Here we will add some protected variables to hold the displayed album and whether the user has made any changes to this album.

CREATE SOME CLASS VARIABLES (continued)

These variables are required to implement all of our new menu items in this chapter. With these in place, it is time to do just that.

6.2MULTIPLE FILE SELECTION

Now that we have an album in our MainForm class, albeit an empty one, we can add photos to it. In previous chapters, we allowed the user to read in a single photo, first using a button and later with a menu item. In our new structure, this has been replaced by the ability to add multiple photos to the album or remove the current photo from the album. Since this code builds on our original Load handler, it is a good place to begin.

As you would expect, we will provide Click handlers for both the Add and Remove items. The Add menu should allow one or more photos to be selected and added to the album, while the Remove menu should delete the currently displayed photo from the album. The Add menu will use the Multiselect property of the OpenFileDialog class, and is where our catchy section title comes from.

6.2.1ADDING IMAGES TO AN ALBUM

In chapter 3, the Click handler for the Load menu permitted a single file to be selected using the OpenFileDialog class. This made sense when only a single image was managed by the application. In this chapter, the idea of an album permits multiple images to be present at the same time. As a result, our user should also be able to load multiple images at once. This is again done using the OpenFileDialog class, so the code for this handler will be similar to the Click event handler for the

Load menu from chapter 3. The Multiselect property is provided by the OpenFileDialog class to indicate whether multiple files can be selected in the dialog. This and other members specific to this class are summarized in .NET Table 6.1.