•Interacting with toolbar buttons.

•Creating and managing image lists.

•Providing tool tips for controls in a form.

We begin our discussion with toolbars.

13.1TOOLBARS

Toolbars were added to windowing environments as an alternate shortcut method for common tasks, especially menu bar items. While keyboard shortcuts are fine for more experienced users, they do not have a graphical presence in the window. Toolbars provide a graphic for each shortcut button, so users should be able to quickly perform common tasks without the need to hunt through the menus or documentation all the time.

At least that was the theory. Personally, I prefer keyboard shortcuts, and find the plethora of toolbars a distraction in many interfaces. While common tasks such as opening and closing a file or selection of a bold or italic font style have developed somewhat standard graphical buttons, I have trouble deciphering many of the tiny graphics shown on many toolbars and pre-

fer to search for keyboard shortcuts instead. When creating toolbars in your programs, make sure their meaning is clear, and do not use a toolbar as an excuse to avoid keyboard shortcuts and access keys. Some users prefer the keyboard over the mouse, so it is a good idea to provide keyboard as well as mouse access to program functions.

But I digress. Let’s get back to toolbars in .NET. Whether you employ them yourself or not, your users will likely expect them. In this section we will look at the ToolBar class in detail, create a blank toolbar in our MyPhotos project, and also introduce the ToolBarButton class.

Later sections will look at image lists and the creation of the various kinds of toolbar buttons. By the end of section 13.3, our efforts will produce the interface shown in figure 13.1.

13.1.1THE TOOLBAR CLASS

As you might expect, there is a ToolBar class in the Windows Forms namespace, and a corresponding .NET Table with some details about this class, namely .NET Table 13.1. A ToolBar control is a bit like the StatusBar or TabControl objects, in that they all serve primarily as containers for other graphical objects.

.NET Table 13.1 ToolBar class

The ToolBar class represents a control that displays ToolBarButton objects on a form. Such objects typically provide shortcuts to menu commands and other commonly used tasks. This class is part of the System.Windows.Forms namespace, and inherits from the Control class. See .NET Table 4.1 on page 104 for a list of members inherited from Control.

13.1.2ADDING A TOOLBAR

A toolbar is typically docked to the top of a window, although it can also be docked to the left, right, or bottom of a form. The following steps add a toolbar to the top of our MainForm window.

Set the version number of the MyPhotos application to 13.1.

As you can see, the Dock property of a ToolBar is set to Top by default. Visual Studio also sets the DropDownArrows and ShowToolTips properties to true, even though the default for both settings is false.

The code generated here is nothing unusual, so we will move on to the

BarButton class.

13.1.3THE TOOLBARBUTTON CLASS

By themselves, toolbars do not present much information to the user. These objects take on meaning and purpose once they have one or more toolbar buttons placed on them. In this section we look at the ToolBarButton class in some detail. We will hold off discussing exactly how to place our buttons on the toolbar until section 13.3, after we have introduced the idea of an image list in section 13.2.

An overview of the ToolBarButton class appears in .NET Table 13.2. This object is a component, so it does not inherit any properties from the Control class. As a result, a number of control-like properties such as Enabled, Tag, and Visible are defined explicitly by this class.

.NET Table 13.2 ToolBarButton class

The ToolBarButton class represents a button that appears within a toolbar control. These buttons typically provide shortcuts to menu commands and other commonly used tasks for the associated form. This class is part of the System.Windows.Forms namespace, and inherits from the System.ComponentModel.Component class.

Toolbar buttons can display a text string, an image, or both an image and text. They appear in one of four styles, based on the Style property setting. The possible styles are defined by the ToolBarButtonStyle enumeration. The values in this enumeration appear in .NET Table 13.3. In our application, we will create at least one button in each style in order to see how these appear in our toolbar.

.NET Table 13.3 ToolBarButtonStyle enumeration

The ToolBarButtonStyle enumeration specifies the various styles available to toolbar buttons placed within a toolbar. The style for a specific ToolBarButton is defined by the Style property for that button.

As for images on our buttons, we will use the common images provided by Microsoft with Visual Studio .NET. These are installed by default into the directory “C:\Program Files\Microsoft Visual Studio .NET\Common7\Graphics,” and we will continue to use the term common image directory introduced in chapter 12 to refer to this directory. If you are not using Visual Studio, have not installed these files, or are feeling especially creative, you can construct or find your own image files here instead of the common ones employed in the examples.

We will create ten toolbar buttons altogether in order to demonstrate various styles and behaviors. The following table summarizes the name, style, and purpose of each button. It also shows the menu item associated with each button. In most cases, clicking a toolbar button will be identical to selecting the associated menu item.

Toolbar buttons for our application

Each of these buttons, except the separators, of course, will require a different image. The images placed on toolbar buttons are stored in an ImageList object associated

with the parent toolbar. Image lists are used by a number of Windows Forms controls to manage the images displayed or available within the control. As a result, we will hold off on creating our toolbar buttons until section 13.3 in order to take a look at this rather important construct.

13.2IMAGE LISTS

There are a number of controls that require one or more images in order to display their contents. Often, the requirement is for a set of images, rather than a single image. For example, the set of toolbar buttons in a ToolBar object, or the images required for a set of Button controls on a form. The Windows Forms namespace provides the ImageList class for managing such collections of images. As we shall see in chapters 14 and 15, this class is also utilized by the ListView and TreeView controls.

This section examines the ImageList class in some detail, and creates a set of images for use in the toolbar we created in the previous section.

.NET Table 13.4 ImageList class

The ImageList class represents a collection of Image objects. Typically, this class is used to support one or more Windows Forms controls in the management and display of images within the control. Classes that use image lists include the Button, ToolBar, ListView, and TreeView classes. This class is part of the System.Windows.Forms namespace, and inherits from the System.ComponentModel.Component class.

13.2.1THE IMAGELIST CLASS

The ImageList class, summarized in .NET Table 13.4, provides a convenient way to store and access images required by various objects. An ImageList component