Use text boxes, masked text boxes, rich text boxes, group boxes, check boxes, radio buttons, and picture boxes effectively.. Chapter Highlights: OBJECTS PROPERTIES PROPERTIES METHODS
Trang 1Solution manual for Programming in Visual Basic
2010 1st Edition by Bradley Millspaugh
Chapter 2 User Interface Design
OBJECTIVES:
Upon completion of this chapter, your students will be able to
1 Use text boxes, masked text boxes, rich text boxes, group boxes, check boxes,
radio buttons, and picture boxes effectively
2 Set the BorderStyle property to make controls appear flat or three-dimensional
3 Select multiple controls and move them, align them, and set common properties
4 Make your projects easy for the user to understand and operate by defining access
keys, setting an Accept and a Cancel button, controlling the tab sequence, resetting the focus during program execution, and causing ToolTips to appear
5 Clear the contents of text boxes and labels
6 Make a control visible or invisible at run time by setting its Visible property
7 Disable and enable controls at design time and run time
8 Change text color during program execution
9 Code multiple statements for one control using the With and End With statements
10 Concatenate (join) strings of text
11 Download the line and shape controls, add them to the toolbox, and use the controls on
your forms
Chapter Highlights:
OBJECTS PROPERTIES PROPERTIES METHODS STATEMENTS
LineShape CancelButton ToolTip on ToolTip1
MaskedTextBox Checked Visible
OvalShape ForeColor WordWrap
PictureBox Image
RadioButton Multiline
RectangleShape SizeMode
RichTextBox StartPosition
Text box TabIndex
ToolTip component TabStop
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Trang 2CHAPTER OUTLINE:
I Introducing More Controls
Review Question 1
Text boxes are used primarily for user input The Text property holds the value input by the user You also can assign a literal to the text property during design time or run time.
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Trang 3wrap to multiple lines The text will wrap to the width of the control, which must
be tall enough to display multiple lines
Review Question 2
A MaskedTextBox has a Mask property that allows you to specify the data type and format of the input data.
Review Question 3, 4
A RichTextBox is a specialized text box that allows additional formatting of the text.
RichText Boxes have a Multiline and WordWrap property that can allow a long Text property to wrap to multiple lines The text will wrap to the width of the control, which must be tall enough to display multiple lines.
D Displaying Text on Multiple Lines
E Group Boxes
F Check Boxes
Review Question 5, 6
Check boxes and radio buttons allow the user to make choices In a group of radio buttons, only one can be selected; but in a group of check boxes, any number of the boxes may be selected.
The current state of check boxes and radio buttons is stored in the Checked property; the CheckChanged event occurs when the user clicks on one of the controls.
Review Question 7
Picture box controls hold a graphic, which is assigned to the Image property Set the SizeMode property to StretchImage to make the image resize to fit the control.
I Using Smart Tags
J Using Images for Forms and Controls
The Resources tab of the Project Designer can be used to add, remove, and rename images in the project Resources folder.
Forms and controls can display images from the project’s resources Use the form’s BackgroundImage property and a control’s Image property.
K Setting a Border and Style
The BorderStyle property of many controls can be set to None, Fixed Single, or Fixed3D, to determine whether the control appears flat or three-dimensional.
L Drawing a Line
Review Question 8
A Selecting Multiple Controls
You can select multiple controls and treat them as a group, including setting common properties at once, moving them, or aligning them.
B Deselecting a Group of Controls
C Moving Controls as a Group
D Setting Properties for Multiple Controls
E Aligning Controls
III.Designing Your Applications for User Convenience
A Designing the User Interface
control size and placement, access keys, default and Cancel buttons, and tab order
Review Question 9
Define keyboard access keys by including an ampersand in the Text property of buttons,
Trang 4radio buttons, check boxes, and labels
C Setting the Accept and Cancel Buttons
Review Question 10
Set the AcceptButton property of the form to the desired button so that the user can press Enter to select the button If you set the form's CancelButton property to a button, that
button will be selected when the user presses the Esc key
Review Question 12, 13
The focus moves from control to control as the user presses the Tab key The sequence for tabbing is determined by the TabIndex properties of the controls The Tab key stops only on controls that have their TabStop property set to True.
E Setting the Form’s Location on the Screen
Add a ToolTip control to a form and then set the ToolTip on ToolTip1 property of a control to make a ToolTip appear when the user pauses the mouse pointer over the control You can set the properties of the ToolTip component to modify the background, the foreground, shape, and an icon for the ToolTips.
Review Question 15
A Clearing Text Boxes and Labels
Clear the Text property of a text box or a label by setting it to an empty string Text boxes
also can be cleared using the Clear method
Review Question 14
To make a control have the focus, which makes it the active control, use the Focus method Using the Focus method of a text box makes the insertion point appear in the text box You cannot set the focus to a disabled control.
C Setting the Checked Property of Radio Buttons and Check Boxes
You can set the Checked property of a radio button or check box at run time and also set the Visible property of controls in code.
D Setting Visibility at Run Time
E Disabling Controls
F Setting Properties Based on User Actions
G Changing the Color of Text
You can use the color constants to change colors during run time.
H Using Radio Buttons for Selecting Colors
I Changing Multiple Properties of a Control
Review Question 16
The With and End With statements provide an easy way to refer to an object multiple times
without repeating the object’s name
Review Question 17
J Concatenating Text
Joining two strings of text is called concatenation and is accomplished by placing an
ampersand between the two elements (A space must precede and follow the
ampersand.)
Visual Basic 2010 offers implicit line continuation as well as the traditional:Use a space and an underscore to continue a long statement on another line Be sure to demonstrate implicit continuation!
L Downloading and Using the Line and Shape Controls
V.Your Hands-On Programming Example
A Planning the Project
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Review Question 18
Trang 5B The Project Coding Solution
VIII Key Terms
IX Review Questions
X Programming Exercises
XI.Case Studies
TEACHING SUGGESTIONS:
You can use any graphic file (with the proper format) that you have available
Demonstration Idea: The hands-on example in the back of chapter 2 can be used as your
demonstration model The example uses many of the new controls and topics introduced in this chapter The Basic code used in the example is brief, and will keep your student's attention Begin by explaining the purpose of the project and talk through, or write on the board, each of the three
planning steps: (1) sketch the form, (2) list the objects and properties that are needed, and (3) plan the code that will be used for each of the procedures that will execute when your project runs.
Chapter 2 introduces many new objects and properties Beginners are often confused about the difference between labels and text boxes Give examples of situations where text boxes are used, such as a form that will be filled in for an employment application Remember, a user can change what is displayed in a text box
There are many options available for customizing the user interface The BorderStyle
property is used for displaying controls as flat or 3D The TextAlign property is used to change the alignment of the text in text boxes The ForeColor (color of text) property can be used to enhance the appearance of the user interface Recommend that your students read
"Designing the User Interface" from Chapter 2 This section of the text suggests colors and fonts that are "comfortable" for the user
The MaskedTextBox and the RichTextBox controls are specialized forms of the TextBox control With the MaskedTextBox you can specify the format of the data required of the user by selecting from the options in the Mask property The RichTextBox allows formatting within the box.
Deciding whether to use a radio button or a check box can be confusing Quiz your
students on what would be used in each of these situations on a credit application:
Your income range—below $25,000, $25,000 to $59,999, above $60,000 (radio
buttons) The ages of your children—under 3, 4-6, 7-10, 11-13, over 13 (check boxes)
Number of years with current employer—less than 1, 2-4, 5 or more (radio buttons) Types
of current credit—Department Store, Gasoline, Home Loan, Other (check boxes)
Pictures can be placed on a form with a PictureBox control Images are added to a project using the Resources dialog box This dialog box appears when the programmer clicks on the Image property and clicks on the properties button
Trang 6 Demonstrate how controls can be selected individually or as a group Show how controls can be moved as a group and properties can be set as a group Demonstrate how multiple controls can be aligned by selecting the group and then using the buttons on the Layout toolbar or the corresponding items on the Format menu
HELPFUL HINT! To change the picture in the form’s Title bar, change the form’s Icon property.
Explain that user convenience is important Changing the Text property to include the "&" will allow keyboard access with the ALT key Emphasize that programmers should be careful not to assign duplicate access keys on the same form
Demonstrate how you can make one of your buttons the default button by setting the
AcceptButton property of the form to the button name When the user presses ENTER, that button is automatically selected and the code in the button executes Also, demonstrate how you can select a cancel button The cancel button is the button that is selected when the user presses the ESC key You can make a button the cancel button by setting the form's
CancelButton property Note that these are properties of the form
Demonstrate and discuss the importance of having the tab key work properly by setting the
TabIndex and TabStop properties You can also view the tab indexes of all controls in the design view by selecting the View menu and then choosing Tab Order (the form must be displayed).
Show how you can set the StartPosition property of a form to specify its location when the form is displayed This is useful for all forms that are not maximized
Add a Tooltip to a control and then run the program and let the mouse pointer pause over the object Note that a ToolTip component must be added to the component tray in order for the controls on the form to have the Tooltip on ToolTip1 property
COMMON ERROR: When students write code to clear a text box or label, many times they will not use an empty string The empty string is "" (no space between the two quotation marks) Often, students will type a blank space in between the quotes This will cause them frustration in later chapters when they are validating text boxes for input and the test finds a blank space and identifies the object as not being empty
Explain the use of the Focus method to make the insertion point appear in the correct object
Note that the Checked property of radio buttons and check boxes can be tested for True or False to determine if they are selected
Discuss the real advantage of using the With statement Using With/EndWith is more efficient than spelling out the object in each statement Your Visual Basic projects will run a little faster
if you use With/EndWith On a large, complicated project, the savings can be significant.
Practice concatenation with these examples:
MessageLabel.Text = "One, " & "Two, " & "Three"
NameLabel.Text = "John " & "Doe"
WeatherLabel.Text = "Hello, " & NameTextBox.Text & "! Today the weather is warm." Don’t forget punctuation in your concatenation:
MessageLabel.Text = "Hello, my name is " & NameTextBox.Text & "."
Don’t forget to demonstrate implicit line continuation, new in Visual Basic
2010! 2-6
Trang 7Chapter 2 – User Interface Design
ANSWERS TO REVIEW QUESTIONS
1 You can display program output in a text box or a label When should you use a text
box? When is a label appropriate?
Use a text box control when you want the user to type some input Use a label control when you want to display information that the user cannot change Labels can be used to display a message or the result of a calculation
2 What would be the advantage of using a masked text box rather than a text box?
The masked text box control is a specialized form of the TextBox control You can specify the format (the Mask property) of the data required of the user, for example, a zip code, a date, a phone number, or a social security number At run time, the user cannot enter characters that do not
conform to the mask
3 When would it be appropriate to use a rich text box instead of a text box?
The rich text box offers a variety of formatting features that are not available in text boxes In a rich text box, the user can apply character formatting, much like using a word processor It would
be appropriate to use a rich text box whenever text should be formatted, or if the text will flow over multiple lines
4 What properties of a TextBox and RichTextBox must be set to allow a long Text property
to wrap to multiple lines?
In order for text boxes and rich text boxes to wrap to a second line, the WordWrap and Multiline properties must be set to True The WordWrap property determines whether the contents should wrap to a second line if they do not fit on a single line The property is set to True by default on both the text box and the rich text box The TextBox and the RichTextBox controls have a Multiline property, which is set to False by default on a text box, and to True on a rich text box
5 How does the behavior of radio buttons differ from the behavior of check boxes?
Radio buttons allow the user to select only one button of a group In any group of check boxes, any number of boxes may be selected
6 If you want two groups of radio buttons on a form, how can you make the groups operate independently?
In order to create two groups of radio buttons that operate independently, you should place each group inside of its own group box A group of radio buttons inside a group box function together as
a group The best method is to first create a group box and then draw each radio button inside the group box Don’t place the radio button on the form and drag it inside the group box — if you do, it will still belong to the form’s group, not to the group in the group box Repeat the process to create another group box with radio buttons
7 Explain how to make a graphic appear in a picture box control
A PictureBox control can hold an image You can set a picture box’s Image property to a graphic file with an extension of bmp, gif, jpg, jpeg, png, ico, emf or wmf Add your images to the project's resources, then assign the resource to the Image property of the PictureBox control Place a PictureBox control on a form and then select its Image property in the Properties window Click on the Properties button to display a Select Resource dialog box where you can select images that you
Trang 8have already added, or add new images Click on the Import button of the Select Resource dialog box to add images An Open dialog box appears where you can navigate to your image files
PictureBox controls have several useful properties that you can set at design time or run time For example, set the SizeMode property to StretchImage to make the picture enlarge to fill the
control You can set the Visible property to False to make the picture box disappear
8 Describe how to select several labels and set them all to 12-point font size at once
There are several methods of selecting multiple controls If the controls are near each other, the easiest method is to use the mouse to drag a selection box around the controls Point to one corner of
a box surrounding the controls, press the mouse button, and drag to the opposite corner When you release the mouse button, each control will have selection handles
You can also select multiple controls, one at a time Click on one control to select it, hold down the Ctrl key or the Shift key, and click on the next control You can keep the Ctrl or Shift key down and continue clicking on controls you wish to select Ctrl–click (or Shift–click) on a control a
second time to deselect it without changing the rest of the group
With the labels selected, scroll to the Font property and click on the plus sign to the left (of the Font property) to open the font options Change the Size property to 12 and press Enter
9 What is the purpose of keyboard access keys? How can you define them in your project? How do they operate at run time?
Many people prefer to use the keyboard, rather than a mouse, for most operations Windows is set up
so that most everything can be done with either the keyboard or a mouse You can make your
projects respond to the keyboard by defining access keys, also called hot keys
You can set access keys for buttons, radio buttons, and check boxes when you define their Text properties Type an ampersand (&) in front of the character you want for the access key; Visual Basic underlines the character
During run time you can operate the keyboard access keys by pressing and holding Alt + the key that corresponds to the underlined character For example, use the Exit button with Alt + x
10 Explain the purpose of the AcceptButton and CancelButton properties of the form Give an example of a good use for each
Once a person’s fingers are on the keyboard to type, most people prefer to press common keys rather than pick up the mouse If one of the buttons on the form is the default button, pressing Enter
is the same as clicking the button
You can make one of your buttons the default button by setting the AcceptButton property of
the form to the button name When the user presses Enter, that button is automatically selected You can also select a cancel button The cancel button is the button that is selected when the user presses the Esc key You can make a button the cancel button by setting the form's CancelButton property A good example of when to use these properties is on a form with OK and Cancel buttons You may want to set the form's AcceptButton property to OkButton and the CancelButton property
to CancelButton
11 What is a ToolTip? How can you make a ToolTip appear?
ToolTips are those small labels that pop up when you pause (rest) your pointer over a toolbar button
or control
To define ToolTips, select the ToolTip control from the toolbox and click anywhere on the form The new control appears in the component tray that opens at the bottom of the Form Designer After you add the ToolTip control, examine the properties list for other controls on the form, such as buttons, text boxes, labels, radio buttons, check boxes, and even the form itself Each has a new ToolTip on ToolTip1 property (assuming that you keep the default name, ToolTip1, for the control) Now you can change the ToolTip on ToolTip1 property to the text that you want displayed when the pointer pauses on the object
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Trang 912 What is the focus? How can you control which object has the focus?
In Windows programs, one control on the form always has the focus You can see the focus
change as you Tab from control to control For controls such as buttons, the focus appears as a thick blue border For text boxes, the insertion point (also called the cursor) appears inside the box Some controls can receive the focus, others cannot For example, text boxes and buttons can
receive the focus, but labels and picture boxes cannot
When a program begins running, the focus is on the control with the lowest TabIndex Using code, the Focus method allows the programmer to control which object has the focus For example,
NameTextBox.Focus() will make the insertion point (focus) appear in a textbox named
NameTextBox
13 Assume you are testing your project and don’t like the initial position of the insertion point Explain how to make the insertion point appear in a different text box when the program begins
When your program begins running, the focus is on the control with the lowest TabIndex (usually 0) Set the TabIndex to 0 for the control where you want the insertion point to appear when the program begins
14 During program execution you want to return the insertion point to a text box called
AddressTextBox What Basic statement will you use to make that happen?
AddressTextBox.Focus()
15 What Basic statements will clear the current contents of a text box and a label?
You can clear out the contents of a text box or label by setting the property to an empty string Use
"" (no space between the two quotation marks) or String.Empty
For example: AddressTextBox.Text = "" or NameLabel.Text = ""
or AddressTextBox.Text = String.Empty
You can also clear out a text box using the Clear method: AddressTextBox.Clear()
16 How are the With and End With statements used? Give an example
The With and End with statements are used to change several properties of a single control You specify an object name in the With statement All subsequent statements until the End With relate to that object The statements beginning with With and ending with End With are called a With block The statements inside the block are indented for readability The real advantage of using the With statement, rather than spelling out the object for each statement, is that With is more efficient Your Visual Basic projects will run a little faster if you use With On a large, complicated project, the savings can be significant
Example:
With TitleTextBox
.Visible = True
.ForeColor = Color.Blue
.Focus()
End With
17 What is concatenation and when would it be useful?
Concatenation is a process whereby you can "tack" one string of characters to the end of another Use an ampersand (&), preceded and followed by a space, between the two strings Concatenating
is very useful when you want to join a string literal and a property
For example: MessageLabel.Text = "Your name is: " & NameTextBox.Text & "."
18 Explain how to continue a very long Basic statement onto another line
When a Basic statement becomes too long for one line, use a line-continuation character You can type
a space and an underscore at the end of the line, press Enter, and continue the statement on the
Trang 10next line It is OK to indent the continued lines The only restriction is that the line-continuation
character must appear between elements; you cannot place a continuation in the middle of a literal, or split the name of an object or property
CHAPTER TOPICS COVERED IN THE PROGRAMMING EXERCISES
Solutions for each of the Programming Exercises are available on the Web site for this
textbook Checkmarks appear in the following tables to outline the chapter topics used in the
solution of each exercise A brief description for each Programming Exercise is given Please
refer to the textbook for complete instructions
2.1 Switch a light bulb on and off Use concatenation
OBJECTS PROPERTIES PROPERTIES METHODS STATEMENTS
CheckBox AcceptButton Text Enable With
GroupBox BorderStyle TextAlign Focus End With
LineShape CancelButton ToolTip on ToolTip1
MaskedTextBox Checked Visible
OvalShape ForeColor WordWrap
PictureBox Image
RadioButton Multiline
RectangleShape SizeMode
RichTextBox StartPosition
Text box TabIndex
ToolTip TabStop
2.2 Display the flag of 4 different countries OBJECTS PROPERTIES PROPERTIES METHODS STATEMENTS CheckBox AcceptButton Text Enable With GroupBox BorderStyle TextAlign Focus End With LineShape CancelButton ToolTip on ToolTip1
MaskedTextBox Checked Visible
OvalShape ForeColor WordWrap
PictureBox Image
RadioButton Multiline
RectangleShape SizeMode
RichTextBox StartPosition
Text box TabIndex
ToolTip TabStop
2.3 Display a weather report Use concatenation
OBJECTS PROPERTIES PROPERTIES METHODS STATEMENTS CheckBox AcceptButton Text Enable With GroupBox BorderStyle TextAlign Focus End With LineShape CancelButton ToolTip on ToolTip1
MaskedTextBox Checked Visible
OvalShape ForeColor WordWrap
PictureBox Image
RadioButton Multiline
RectangleShape SizeMode
RichTextBox StartPosition
Text box TabIndex
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