Visual studio 2010 part 24 pdf

Key Skills & Concepts● Perform Screen Layout ● Use Controls ● Work with Data in the UI Windows Presentation Foundation WPF is a .NET technology for building desktop applications.. The XA

Building Desktop

Applications with WPF

Key Skills & Concepts

● Perform Screen Layout

● Use Controls

● Work with Data in the UI

Windows Presentation Foundation (WPF) is a NET technology for building desktop

applications The result of building a WPF application is an *.exe file that you can run directly on your computer or deploy and run on any other computer that has NET installed With WPF, you can add a graphical user interface (GUI), pronounced “Gooey,” that makes it easier for users to work with your program This chapter will show you how

to lay out a screen in WPF and explain the controls, such as Button and TextBox, that you can place on the screen You’ll also learn how to capture events off controls, allowing you

to add code that runs based on user input Since most applications work with data, this chapter builds on what you learned in Chapter 7 and shows how to bind data to controls in the GUI

This chapter will show you how to build a WPF GUI with the VS Designer, but sometimes you must work at a lower level and manipulate the XAML, pronounced

“Zammel,” that defines the GUI XAML is an XML format that WPF and Silverlight use to define a GUI There are two appendixes in this book that will help you get up to speed in XAML: Appendix A, “Introduction to XML,” and Appendix B, “Introduction to XAML.” If you aren’t familiar with XML, start with Appendix A However, if you have

a good grasp of basic XML syntax, go straight to Appendix B I’ll try to explain WPF in

a way that any XAML you see can be understood in its context, but you might want to review the appendixes to avoid any confusion Once you’re familiar with XAML, you can return here and start with the next section, which explains how to start a WPF project

Starting a WPF Project

In Chapter 5, you learned how to create and build projects The example explained how

to create a Console application However, what you learned there is generally applicable

to most other application types This section builds upon what you already know about projects and explains what is unique to a WPF application To get started, open the New Project window; select WPF Application; and fill in the project name, location, and

solution name I’m naming the examples in the chapter as MyShop to continue the idea

of customers who buy products that started in Chapter 7 when discussing data Figure 8-1

shows the new WPF application in VS, including a Toolbox, a Designer, and a Solution

Explorer The Toolbox contains controls, which are user interface (UI) elements, such as

Button and Textbox, that you can drag and drop onto the Designer

NOTE

There is another NET technology, Windows Forms, for creating desktop applications

This book doesn’t discuss Windows Forms because it’s an older technology The way

forward for desktop application development is WPF, and the intention of this book is to

help guide you in a direction most beneficial to you.

The Designer allows you to lay out the UI of the application; it is divided into Design

on the top and XAML on the bottom The Design surface allows you to visually work

with controls and layouts of those controls The XAML editor allows you to work with

the XML representation of the controls on the design surface The Design and XAML are

interrelated because a change in one causes a change in the other For example, if you add

a Button to the Design, you’ll see the XML representation of that Button in the XAML

Figure 8-1 A new WPF application project

Similarly, if you add a TextBox element to the XAML, you’ll see the visual representation

of that TextBox in Design

You have various controls for manipulating the windows Both Design and XAML have zoom controls The zoom tool on Design is a slider in the upper-left corner, and zoom for XAML is a drop-down control in the lower-left corner You can also zoom by clicking either Design or XAML and moving the mouse wheel At the upper right of the XAML editor (bottom right of the Design surface), you can switch between horizontal and vertical splits of the window or click the chevron to collapse the XML The splitter icon below the chevron allows you to split the XAML editor into two if you drag it down The up-down arrow between the Design and XAML tabs allows you to switch sides so that each panel shows where the other was Locating the carat in the middle of the separator between Design and XAML allows you to resize each window

Understanding Layout

A layout defines how you can position and size controls on a screen WPF windows and controls have a Content (can occasionally be called something else) property that accepts

a single control In some cases, such as a Button control, the content can be text However, many situations call for the ability to lay out multiple controls This section concentrates

on performing layout in windows, and a Window has a Content property that accepts only one control; that one control should be a layout control, which is the subject of this section

WPF includes several layout controls, including Grid, StackPanel, DockPanel, WrapPanel, and Canvas By default, VS will generate a window with a Grid as the layout control However, you are free to replace the Grid with any other layout control that suits your needs This section will show you how to use each of these controls

Grid Layout

Whenever starting a new WPF project, VS adds a Grid A Grid is a layout control that

allows you to create a set of rows and columns that hold other controls You can add rows and columns to a Grid through the Visual Designer by clicking in the middle of a window

in design view Figure 8-2 shows a column being added to a Grid

The thin vertical line in the middle of the window is a new border between two columns After clicking the window, you’ll see two thick borders on the left and top of the window While you hover over the top border, VS draws a vertical line that moves left and right as you run your mouse along the top border You can do the same with the left border, adding rows to the Grid This is a very quick way to add rows and columns to a Grid

The arrow in the Grid border allows you to reposition the column or row border

You can remove the column or row border by selecting the arrow in the Grid border and

dragging the arrow off the window

CAUTION

Don’t press the DELETE key when you have a border selected You’ll accidentally delete

your Grid, which you might have spent some time on If you want to remove a column

or row, grab the arrow for the border you want to remove and drag the border off the

window.

Once you’ve created rows and columns, you can add further customizations that

define how much space the column or row can take There are three sizing customizations: fixed, weighted, and auto To set each of these options, hover over the column or row

border and VS will display a sizing panel, as shown over the left column design border in

Figure 8-3

The diamond icon on the left means fixed, where the size will stay the same The asterisk

icon in the middle is a weighted proportion, where the size stays the same in relation to

the other columns The rightmost icon is auto, meaning that the size will vary according to

Figure 8-2 Adding columns and rows to a Grid

whatever space remains after the other columns’ sizes are set After you’ve added content to your Grid, you can use these sizing options to experiment with the layout that you want One thing to notice in Figure 8-3 is the number in the Grid border for each row and column These numbers tell you the size in pixels for each row and column they appear upon

Figure 8-3 also shows the Properties window on the right, where you can select and customize the Column and Row collections

True to the purpose of the Grid, Figure 8-3 shows controls that have been added to the Grid, placed in each cell of the Grid Another popular layout control is StackPanel, discussed next

StackPanel Layout

The StackPanel is ideal for when you want to lay out controls each on top of the other, like

a stack You can use a StackPanel by dragging the StackPanel control from the Toolbox onto the design surface If you want to use the StackPanel as your primary layout, you can Figure 8-3 Column and row sizing options

select the grid, which is added by default to a new project, and delete the Grid Figure 8-4

shows a StackPanel that contains multiple button controls

In Figure 8-4, it doesn’t matter where you try to lay the buttons—the StackPanel will

always lay them out one after the other In addition to vertical layout, the StackPanel can

lay out controls horizontally Just change the Orientation property, shown in the Properties

window in Figure 8-4, to Horizontal Next, you’ll learn how to dock controls to the sides

of a container

DockPanel Layout

You’ve seen how VS allows you to dock windows within the borders of the application

This helps you organize your screen so that you can use many tools at one time You can

lay out your controls the same way with the DockPanel control

Get started by dragging and dropping a DockPanel control from the Toolbox to the

Window in the design surface You might want to delete the default Grid first Also, the

DockPanel initializes with a Height and a Width, which you’ll probably want to remove

by selecting the DockPanel, opening the Properties window, and clearing the Height and

Figure 8-4 Using a StackPanel layout

Width properties Removing the Height and Width properties allows the DockPanel to

expand and cover the entire window Figure 8-5 shows a DockPanel with Label controls in each docking position

Every time you drag and drop a control onto the design surface of a DockPanel, the control will take the center position by default To specify where the control should dock,

open the Properties window and set the DockLayout.Dock property When you add a new

control, the new control will become the center control and the other control will dock to

the side of the DockPanel you specified in the Dock property The next layout control is

WrapPanel

WrapPanel Layout

Whenever controls should naturally follow each other in sequence and continue wrapping

on new lines, you can use a WrapPanel Examples of when this is useful could be when adding controls that contain text and it’s useful to view the controls in sequence Figure 8-6 shows several CheckBox controls in a WrapPanel

Figure 8-5 DockPanel layout

Figure 8-6 demonstrates how you can lay out a group of controls to fill an available

space In the case of the CheckBox controls, the Orientation of the WrapPanel is set to

Vertical (the default is Horizontal) When the number of CheckBox controls fills the

vertical column, remaining CheckBoxes wrap to the next column Because the sizes of the CheckBox controls are the same, you have a uniform layout, which is easier than trying

to do the same thing with a Grid or other layout control The final layout control we’ll

discuss is the Canvas, which is next

Canvas Layout

There are times when you might want to perform explicit layout of controls If you

were building a diagramming application or a drawing program, or if you just wanted to

explicitly specify the location of controls, the Canvas layout will work fine Figure 8-7

shows some controls on a Canvas layout

The Rectangle and Ellipse controls were dragged and dropped from the Toolbox onto

the Canvas control Notice the Canvas.Left, Canvas.Top, Width, and Height properties in the

Properties window, demonstrating the absolute positioning of the selected Ellipse control

Figure 8-6 The WrapPanel Layout control

Now that you know how to use the layout controls, the next section takes a closer look

at WPF controls in general, giving you tips on how to use them in your application

Using WPF Controls

WPF includes many controls for helping you build user interfaces This section groups the controls into categories, including text, selection, containers, information, shapes, and decorators Data controls are excluded on purpose because the section following controls

is “Working with Data in WPF.” Before diving into each control, let’s do an overview of the VS environment associated with control work

Managing Windows for Controls

When working with controls, you’ll be working with four different windows: Toolbox, Solution Explorer, Designer, and Properties You learned how to access each of these windows in earlier chapters; but as a convenience, Table 8-1 gives you a quick summary

on how to open these windows

Figure 8-7 The Canvas Layout control