Set the version number of the MyPhotos application to 7.2.

With this task completed, our way is clear to implement the functionality previously provided by the PictureBox control in our MainForm control directly.

7.2.2HANDLING THE IMAGE MENU

One of the unfortunate but necessary side effects of nuking the PictureBox control is that our processing of the Image menu no longer makes sense. We built this with the PictureBoxSizeMode enumeration values in mind. Since we are no longer using this control, we need to change how our menu works.

As an alternative solution, we will create our own enumerator for this purpose to use in place of the PictureBoxSizeMode enumeration. We could provide a long discussion of the individual changes required here, but this is chapter 7 so we’ll just plunge ahead.

In this section we’ll create the new enumeration and begin the process of modifying our menu handlers. The subsequent sections will address issues specific to the child menu items of the Image menu, and complete our implementation of the menu handlers.

REPLACE THE MODEMENUARRAY MEMBER (continued)

Let’s look at the menu handlers here to see how our new DisplayMode enumeration is used. The Popup event handler is called whenever the Image submenu is about to display, while the Click handler is called whenever an Image submenu is selected.

protected void menuImage_Popup (object sender, System.EventArgs e)

{

if (sender is MenuItem)

{

bool bImageLoaded = ( _album.Count > 0 );

MenuItem miParent = (MenuItem)sender;

foreach (MenuItem mi in miParent.MenuItems)

{

mi.Enabled = bImageLoaded;

mi.Checked = (this._selectedMode == (DisplayMode)mi.Index);

}

}

Cast integer to b enumerated type

}

protected void menuImage_ChildClick (object sender, System.EventArgs e)

{

if (sender is MenuItem)

{

default:

case DisplayMode.StretchToFit:

// Stretch image to fit the display area. this.Invalidate();

break;

case DisplayMode.ActualSize:

// Display image at actual size. this.Invalidate();

break;

}

statusBar1.Invalidate();

}

This code raises some interesting points about the use of enumerated types.

bThis line simply casts an integer value to an enumerated type. With the extensive error and type checking built into C#, you might think it would be an error to cast an integer to an enumeration value that does not exist. In fact, a standard C# enumeration by definition can hold any integer value, so any integer value can be cast to any enumeration type.

cThis line uses a switch statement to perform the appropriate action based on the current display mode setting. Notice how the StretchToFit case is used as the default setting.

dSince our image will now be drawn directly on the form, we need to call the Form.Invalidate method to force the application to redraw the window using the new setting.

Of course, the menuImage_ChildClick method is not finished yet. We will fill this method in as we enable the corresponding display modes.

Before we do, one other feature is missing. Our wonderful context menu disappeared along with the PictureBox control. The menu is still around, of course, and is still initialized by the DefineContextMenu method to contain a copy of the View menu. The menu is just not hooked up to any controls at the moment, so it never appears.

We can fix this by attaching this menu to our Form class. Continuing our previous steps:

Our context menu is now associated with the top-level form, and will appear whenever the user right-clicks anywhere in the window.

Your program may or may not compile here, depending on what you did to the OnPaint method when the _selectedImageMode field was removed. We’ll cover this as part of the next section.

7.2.3IMPLEMENTING THE STRETCH TO FIT OPTION

The modification of our Image menu handlers fully eradicates the PictureBox control from our application. While the PictureBox control created some problems, it also drew the current photograph for us. Now we will need to do this by hand, the result of which is shown in figure 7.2. You will note in this figure that the application is lacking the border previously shown around the image by the PictureBox control. This will be addressed later in the chapter.