Chapter 3: Program Design and Coding 3 Objectives ►Set the Visible property in the Properties window ►Set the Enabled property in the Properties window ►Run a Visual Basic 2015 program
Trang 1Microsoft Visual Basic 2015
CHAPTER THREE
Program Design and
Coding
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Chapter 3: Program Design and Coding 2
Objectives
►Change the color properties of an object
►Add images to a PictureBox object
►Locate and save an image from the web
►Import an image into the Program Resources
folder
►Size an image
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Chapter 3: Program Design and Coding 3
Objectives
►Set the Visible property in the Properties window
►Set the Enabled property in the Properties
window
►Run a Visual Basic 2015 program
►Enter Visual Basic 2015 code
►Understand Visual Basic 2015 code statement
formats
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Chapter 3: Program Design and Coding 4
Objectives
►Use IntelliSense to enter Visual Basic 2015 code
statements
►Use code to set the Visible property of an object
►Use code to set the Enabled property of an object
►Enter comments in Visual Basic 2015 code
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Chapter 3: Program Design and Coding 5
Objectives
►Correct errors in Visual Basic 2015 code
►Write code to use the Close() procedure
►Print code
►Prepare an event-planning document
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Chapter 3: Program Design and Coding 6
BackColor and ForeColor Properties
►Tap or click the Windows Form object to select it
►If necessary, scroll in the Properties window until
the BackColor property is displayed, and then tap
or click the right column of the BackColor property
►Tap or click the BackColor arrow Then, tap or
click the Web tab to display the Web tabbed page
►Scroll to display the color you wish to apply
►Tap or click the color you wish to apply on the
color list
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Chapter 3: Program Design and Coding 7
BackColor Property
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Chapter 3: Program Design and Coding 8
Locating and Saving an Image from the Web
►Open your web browser and navigate to the
webpage containing the image you want to save
►Press and hold or right-click the image, tap or
click Save Picture As, and then navigate to the
location on your computer where you store
downloaded files
►Click the Save button to save the image
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Chapter 3: Program Design and Coding 9
Locating and Saving an Image from the Web
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Chapter 3: Program Design and Coding 10
Importing the Image into the Program Resources Folder
►With Visual Studio 2015 and the desired program open,
select the desired PictureBox object by tapping or clicking
it Scroll in the PictureBox Properties window until the
Image property is visible Tap or click the Image property
name in the left list of the Properties window
►Tap or click the ellipsis button in the right column of the
Image property
►Tap or click the Import button in the Select Resource
dialog box Use the features of the Open dialog box to
locate the file you want to import into the program
►Select the file you want to import
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Chapter 3: Program Design and Coding 11
Importing the Image into the Program Resources Folder
►Tap or click the Open button in the Open dialog
box
►Tap or click the OK button in the Select Resource
dialog box
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Chapter 3: Program Design and Coding 12
Sizing an Image
►Select the PictureBox object to resize, and then
scroll in the Properties window until you see the
SizeMode property Tap or click the SizeMode
property name in the left column, and then tap or click the SizeMode arrow in the right column of
the SizeMode property
►Tap or click StretchImage in the SizeMode list
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Chapter 3: Program Design and Coding 13
Sizing an Image
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Chapter 3: Program Design and Coding 14
Visible Property
►Select the desired PictureBox object Scroll in the
Properties window until the Visible property is
displayed Tap or click the Visible property name
in the left column, and then tap or click the Visible arrow in the right column of the Visible property
►Tap or click False on the Visible property list
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Chapter 3: Program Design and Coding 15
Visible Property
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Chapter 3: Program Design and Coding 16
Enabled Property
►Select the desired object Scroll in the Properties
window until the Enabled property is displayed
Tap or click the Enabled property name in the left column, and then tap or click the Enabled arrow
in the right column of the Enabled property
►Tap or click False on the Enabled property list
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Chapter 3: Program Design and Coding 17
Enabled Property
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Chapter 3: Program Design and Coding 18
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Chapter 3: Program Design and Coding 19
Entering Visual Basic Code for Event Handling
►With Visual Studio 2015 and the desired program
open and the [Design] tabbed window visible,
point to the desired button object in the Windows Form object
►Double-tap or double-click the button object
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Chapter 3: Program Design and Coding 20
Entering Visual Basic Code for Event Handling
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Chapter 3: Program Design and Coding 21
Visual Basic 2015 Coding Statements
►The Visual Basic syntax specifies how each
statement must be written
►When the user taps or clicks a button while the
program is running, an action associated with the coding statement will occur
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Chapter 3: Program Design and Coding 22
General Format of a Visual Basic Statement
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Chapter 3: Program Design and Coding 23
IntelliSense
►IntelliSense displays all allowable entries you
can make in a Visual Basic statement each time a dot (period), equal sign, or other special character
is required for the statement
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Chapter 3: Program Design and Coding 24
Entering a Visual Basic Statement
►With the code window open and the insertion point
positioned where you want to insert the code, type pic
►To identify the correct entry, type its next letter until the
entry is selected
►When IntelliSense highlights the correct object name,
press the key corresponding to the entry that is to follow
the object name In this case, press the PERIOD key
►As with the object name in the second step, the next step
is to enter one or more characters until IntelliSense
highlights the desired property in the list Type the letter v for the Visible property
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Chapter 3: Program Design and Coding 25
Entering a Visual Basic Statement
►Press the key for the character that is to follow
the property name In this case, press the
SPACEBAR
►Press the EQUAL SIGN key on the keyboard and
then press the SPACEBAR and the letter t
►Type t for True
►Press the key for the character that follows the
True entry In this case, press the ENTER key
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Chapter 3: Program Design and Coding 26
Entering a Visual Basic Statement
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Chapter 3: Program Design and Coding 27
Setting the Visible Property to False
►With the insertion point in the desired location,
type pic
►Type the next letter for the button name
►Press the key for the character that is to follow
the object name In this case, press the PERIOD key
►Press the SPACEBAR, press the EQUAL SIGN
key, and then press the SPACEBAR
►Type f and then press the ENTER key
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Chapter 3: Program Design and Coding 28
Setting the Visible Property to False
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Chapter 3: Program Design and Coding 29
Enabled Property
►Type btn to display the IntelliSense list
►Type additional characters in the button name
until IntelliSense highlights the desired entry in
the list
►Type a period, type e, press the SPACEBAR,
press the EQUAL SIGN key, press the
SPACEBAR again, and then type true to select
True in the IntelliSense list
►Press the ENTER key to enter the completed
statement and place the insertion point on the
next line
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Chapter 3: Program Design and Coding 30
Enabled Property
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Chapter 3: Program Design and Coding 31
Comments in Program Statements
►To insert a blank line following the event code
generated by Visual Studio that begins with the
word, Private, tap or click anywhere in that line
and then press the END
►Press the ENTER key
►Type the first line of the comments, beginning
with an apostrophe, and then press the ENTER
key
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Chapter 3: Program Design and Coding 32
Comments in Program Statements
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Chapter 3: Program Design and Coding 33
Same-Line Comments
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Chapter 3: Program Design and Coding 34
Introductory Comments
►Tap or click to the left of the word, Public, on line
1 in the program to place the insertion point on
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Chapter 3: Program Design and Coding 35
Introductory Comments
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Chapter 3: Program Design and Coding 36
Correcting Errors in Code
►Using IntelliSense to help you enter code reduces
the likelihood of coding errors considerably
• One possible error would be to forget an
apostrophe in a comment statement
►A build errors message means the Visual Basic
compiler detected a coding error in the program
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Correcting Errors in Code
Chapter 3: Program Design and Coding 37
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Chapter 3: Program Design and Coding 38
Correcting Errors in Code
►Tap or click the No button in the Microsoft Visual
Studio dialog box that informs you of a build error
►Double-tap or double-click anywhere on the error
line
►Tap or click in the leftmost column on the line
containing the error to place the insertion point at that location
►Type an apostrophe
►Tap or click anywhere in the code window
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Chapter 3: Program Design and Coding 39
Correcting Errors in Code
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Chapter 3: Program Design and Coding 40
Additional Tap or Click Events
►On the [Design] tabbed page, double-tap or
double-click the Exit Window Button object
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Chapter 3: Program Design and Coding 41
Close Procedure
►With the insertion point positioned where you
want the Close statement to appear, type clo to
highlight Close in the IntelliSense list
►Press the ENTER key
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Chapter 3: Program Design and Coding 42
Printing Code
►Tap or click File on the menu bar to display the
File menu
►Tap or click Print on the File menu to display the
Print dialog box
►Ensure that a check mark appears in the Include
line numbers check box if you want line numbers
on your printout Most developers prefer line
numbers on printouts
►Make any other needed selections in the Print
dialog box
►Tap or click the OK button in the Print dialog box
to print the code