Chapter Ten String Manipulation and Menus

Transcription

1 Microsoft Visual Basic 2015: Reloaded Sixth Edition Chapter Ten String Manipulation and Menus

2 Objectives After studying this chapter, you should be able to: Determine the number of characters in a string Remove characters from a string Insert characters in a string Align the characters in a string Search a string Access the characters in a string Compare strings using pattern matching Add a menu to a form Code a menu item s Click event procedure 2

3 Working with Strings Determining the Number of Characters in a String Length Property Contains the number of characters in a string Figure 10-1: How to determine the number of characters in a string 3

4 Removing Characters from a String Trim Method Removes (trims) any space characters from both the beginning and end of a string Remove Method Removes a specified number of characters located anywhere in a string 4

5 Figure 10-2: How to remove characters from a string 5

6 Inserting Characters into a String Insert Method Allows you to insert characters anywhere in a string 6 Figure 10-3: How to insert characters in a string

7 Aligning the Characters in a String PadLeft Method The padded characters at the beginning of the string Doing this right-aligns the characters within the string PadRight Method The padded characters at the end of the string Doing this left-aligns the characters within the string 7

8 8 Figure 10-4: How to align characters in a string

9 Searching a String 9 Figure 10-5: How to search a string (continues)

10 Figure 10-5: How to search a string 10

11 Contains Method Returns the Boolean value True when the substring is contained anywhere in the string IndexOf Method Returns an integer: either 1 or a number that is greater than or equal to 0 The 1 indicates that the substring is not contained in the string A number other than 1 is the character index of the substring s starting position in the string 11

12 Accessing the Characters in a String Substring Method Accesses any number of characters in a string 12 Figure 10-6: How to access characters in a string

13 Using Pattern Matching to Compare Strings Like Operator Allows you to use pattern-matching characters to determine whether one string is equal to another string Figure 10-7: How to use pattern matching to compare strings (continues) 13

14 Figure 10-7: How to use pattern matching to compare strings (continues) 14

15 15 Figure 10-7: How to use pattern matching to compare strings (continues)

16 Figure 10-7: How to use pattern matching to compare strings 16

17 Adding a Menu to a Form Menu Strip Control To include one or more menus on a Form The shortcut keys appear to the right of a menu item and allow the user to select the item without opening the menu Figure 10-8: Location of menu elements 17

18 Adding a Menu to a Form (cont'd.) Figure 10-9: File menu Figure 10-10: Exit command s Click event procedure 18

19 Programming Tutorial 1 Figure 10-11: TOE Chart for the Guess the Word Game Application 19 Figure 10-12: MainForm for the Guess the Word Game Application

20 Programming Tutorial 2 Figure 10-29: Sample run of the Bucky s Burgers Application 20 Figure 10-26: TOE chart and MainForm for the Bucky s Burgers Application

21 Programming Example Figure 10-32: TOE Chart 21 Figure 10-33: MainForm and tab order

22 Summary You use a menu strip control to add one or more menus to a form Each menu title and menu item should have an access key. Commonly used menu items should be assigned shortcut keys Figure contains a summary of the string manipulation techniques covered in the chapter 22

23 Summary (cont'd.) Figure 10-37: String manipulation techniques 23