Tài liệu Introduction to Design Patterns in C#

1. What are Design Patterns? 21
Defining Design Patterns 23
The Learning Process 25
Studying Design Patterns 26
Notes on Object-Oriented Approaches . 26
C# Design Patterns 27
How This Book Is Organized . 28
2. Syntax of the C# Language 29
Data Types 30
Converting Between Numbers and Strings . 32
Declaring Multiple Variables 32
Numeric Constants 32
Character Constants 33
Variables . 33
Declaring Variables as You Use Them . 34
Multiple Equals Signs for Initialization 34
A Simple C# Program . 34
Compiling & Running This Program 36
Arithmetic Operators . 36
Increment and Decrement Operators 37
Combining Arithmetic and Assignment Statements . 37
Making Decisions in C# 38
Comparison Operators 39
Copyright © , 2002 by James W Cooper
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Combining Conditions 39
The Most Common Mistake . 40
The switch Statement 41
C# Comments 41
The Ornery Ternary Operator . 42
Looping Statements in C# . 42
The while Loop . 42
The do-while Statement 43
The for Loop . 43
Declaring Variables as Needed in For Loops . 44
Commas in for Loop Statements . 44
How C# Differs From C . 45
Summary . 46
3. Writing Windows C# Programs . 47
Objects in C# . 47
Managed Languages and Garbage Collection 48
Classes and Namespaces in C# . 48
Building a C# Application 49
The Simplest Window Program in C# 50
Windows Controls 54
Labels 55
TextBox . 55
CheckBox 56
Copyright © , 2002 by James W Cooper
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Buttons 56
Radio buttons 56
Listboxes and Combo Boxes 57
The Items Collection . 57
Menus 58
ToolTips 58
Other Windows Controls 59
The Windows Controls Program 59
Summary . 61
Programs on the CD-ROM . 47
4. Using Classes and Objects in C# 62
What Do We Use Classes For? . 62
A Simple Temperature Conversion Program 62
Building a Temperature Class . 64
Converting to Kelvin . 67
Putting the Decisions into the Temperature Class 67
Using Classes for Format and Value Conversion . 68
Handling Unreasonable Values . 71
A String Tokenizer Class 71
Classes as Objects . 73
Class Containment 75
Initialization 76
Classes and Properties . 77
Copyright © , 2002 by James W Cooper
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Programming Style in C# 79
Summary . 80
Programs on the CD-ROM . 62
5. Inheritance . 81
Constructors 81
Drawing and Graphics in C# . 82
Using Inheritance 84
Namespaces . 85
Creating a Square From a Rectangle . 86
Public, Private and Protected 88
Overloading . 89
Virtual and Override Keywords 89
Overriding Methods in Derived Classes . 90
Replacing Methods Using New 91
Overriding Windows Controls 92
Interfaces . 94
Abstract Classes 95
Comparing Interfaces and Abstract Classes 97
Summary . 99
Programs on the CD-ROM . 99
6. UML Diagrams 100
Inheritance . 102
Interfaces . 103
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Composition 103
Annotation . 105
WithClass UML Diagrams . 106
C# Project Files . 106
7. Arrays, Files and Exceptions in C# . 107
Arrays 107
Collection Objects . 108
ArrayLists 108
Hashtables . 109
SortedLists 110
Exceptions . 110
Multiple Exceptions 112
Throwing Exceptions 113
File Handling . 113
The File Object 113
Reading Text File . 114
Writing a Text File 114
Exceptions in File Handling 114
Testing for End of File 115
A csFile Class 116
8. The Simple Factory Pattern . 121
How a Simple Factory Works . 121
Sample Code . 122
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The Two Derived Classes . 122
Building the Simple Factory . 123
Using the Factory 124
Factory Patterns in Math Computation . 125
Programs on the CD-ROM . 128
Thought Questions 128
9. The Factory Method . 129
The Swimmer Class 132
The Events Classes 132
Straight Seeding 133
Circle Seeding . 134
Our Seeding Program 134
Other Factories 135
When to Use a Factory Method 136
Thought Question 136
Programs on the CD-ROM . 136
10. The Abstract Factory Pattern 137
A GardenMaker Factory . 137
The PictureBox . 141
Handling the RadioButton and Button Events 142
Adding More Classes 143
Consequences of Abstract Factory 144
Thought Question 144
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Programs on the CD-ROM . 144
11. The Singleton Pattern . 145
Creating Singleton Using a Static Method 145
Exceptions and Instances 146
Throwing the Exception 147
Creating an Instance of the Class 147
Providing a Global Point of Access to a Singleton . 148
Other Consequences of the Singleton Pattern . 149
Programs on Your CD-ROM 149
12. The Builder Pattern 150
An Investment Tracker 151
The Stock Factory . 154
The CheckChoice Class 155
The ListboxChoice Class 156
Using the Items Collection in the ListBox Control 157
Plotting the Data 158
The Final Choice . 159
Consequences of the Builder Pattern 160
Thought Questions 161
Programs on the CD-ROM . 161
13. The Prototype Pattern 162
Cloning in C# 163
Using the Prototype . 163
Copyright © , 2002 by James W Cooper
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Cloning the Class 167
Using the Prototype Pattern 170
Dissimilar Classes with the Same Interface 172
Prototype Managers 176
Consequences of the Prototype Pattern . 176
Thought Question 177
Programs on the CD-ROM . 177
Summary of Creational Patterns . 178
14. The Adapter Pattern . 180
Moving Data Between Lists 180
Making an Adapter 182
Using the DataGrid . 183
Detecting Row Selection . 186
Using a TreeView . 186
The Class Adapter . 188
Two-Way Adapters . 190
Object Versus Class Adapters in C# . 190
Pluggable Adapters . 191
Thought Question 191
Programs on the CD-ROM . 191
15. The Bridge Pattern 192
The VisList Classes . 195
The Class Diagram 196
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Extending the Bridge 197
Windows Forms as Bridges 201
Consequences of the Bridge Pattern . 202
Thought Question 203
Programs on the CD-ROM . 203
16. The Composite Pattern . 204
An Implementation of a Composite 205
Computing Salaries . 206
The Employee Classes 206
The Boss Class 209
Building the Employee Tree . 210
Self-Promotion 213
Doubly Linked Lists . 213
Consequences of the Composite Pattern . 215
A Simple Composite . 215
Composites in .NET 216
Other Implementation Issues 216
Thought Questions 216
Programs on the CD-ROM . 217
17. The Decorator Pattern 218
Decorating a CoolButton 218
Handling events in a Decorator . 220
Layout Considerations 221
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Control Size and Position 221
Multiple Decorators 222
Nonvisual Decorators 225
Decorators, Adapters, and Composites . 226
Consequences of the Decorator Pattern 226
Thought Questions 226
Programs on the CD-ROM . 227
18. The Façade Pattern . 228
What Is a Database? 228
Getting Data Out of Databases 230
Kinds of Databases 231
ODBC 232
Database Structure 232
Using ADO.NET . 233
Connecting to a Database 233
Reading Data from a Database Table . 234
dtable = dset.Tables [0]; 235
Executing a Query . 235
Deleting the Contents of a Table . 235
Adding Rows to Database Tables Using ADO.NET 236
Building the Façade Classes . 237
Building the Price Query . 239
Making the ADO.NET Façade 239
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The DBTable class 242
Creating Classes for Each Table . 244
Building the Price Table . 246
Loading the Database Tables 249
The Final Application . 251
What Constitutes the Façade? . 252
Consequences of the Façade . 253
Thought Question 253
Programs on the CD-ROM . 253
19. The Flyweight Pattern 254
Discussion . 255
Example Code . 256
The Class Diagram 261
Selecting a Folder 261
Handling the Mouse and Paint Events 263
Flyweight Uses in C# 264
Sharable Objects . 265
Copy-on-Write Objects . 265
Thought Question 266
Programs on the CD-ROM . 266
20. The Proxy Pattern . 267
Sample Code . 268
Proxies in C# . 270
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Copy-on-Write 271
Comparison with Related Patterns 271
Thought Question 271
Programs on the CD-ROM . 271
21. Chain of Responsibility . 274
Applicability 275
Sample Code . 276
The List Boxes 280
Programming a Help System 282
Receiving the Help Command 286
A Chain or a Tree? 287
Kinds of Requests . 289
Examples in C# . 289
Consequences of the Chain of Responsibility 290
Thought Question 290
Programs on the CD-ROM . 291
22. The Command Pattern . 292
Motivation . 292
Command Objects . 293
Building Command Objects 294
Consequences of the Command Pattern . 297
The CommandHolder Interface 297
Providing Undo . 301
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Thought Questions 309
Programs on the CD-ROM . 310
23. The Interpreter Pattern 311
Motivation . 311
Applicability 311
A Simple Report Example 312
Interpreting the Language . 314
Objects Used in Parsing 315
Reducing the Parsed Stack 319
Implementing the Interpreter Pattern 321
The Syntax Tree 322
Consequences of the Interpreter Pattern . 326
Thought Question 327
Programs on the CD-ROM . 327
24. The Iterator Pattern 328
Motivation . 328
Sample Iterator Code 329
Fetching an Iterator . 330
Filtered Iterators 331
The Filtered Iterator 331
Keeping Track of the Clubs 334
Consequences of the Iterator Pattern 335
Programs on the CD-ROM . 336
Copyright © , 2002 by James W Cooper
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25. The Mediator Pattern . 337
An Example System 337
Interactions Between Controls 339
Sample Code . 341
Initialization of the System . 345
Mediators and Command Objects . 345
Consequences of the Mediator Pattern 347
Single Interface Mediators 348
Implementation Issues . 349
Programs on the CD-ROM . 349
26. The Memento Pattern . 350
Motivation . 350
Implementation . 351
Sample Code . 351
A Cautionary Note 358
Command Objects in the User Interface . 358
Handling Mouse and Paint Events 360
Consequences of the Memento . 361
Thought Question 361
Programs on the CD-ROM . 362
27. The Observer Pattern . 363
Watching Colors Change 364
The Message to the Media 367
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Consequences of the Observer Pattern 368
Programs on the CD-ROM . 369
28. The State Pattern 370
Sample Code . 370
Switching Between States . 376
How the Mediator Interacts with the State Manager 377
The ComdToolBarButton . 378
Handling the Fill State 381
Handling the Undo List . 382
The VisRectangle and VisCircle Classes 385
Mediators and the God Class 387
Consequences of the State Pattern 388
State Transitions 388
Thought Questions 389
Programs on the CD-ROM . 389
29. The Strategy Pattern . 390
Motivation . 390
Sample Code . 391
The Context . 392
The Program Commands 393
The Line and Bar Graph Strategies . 394
Drawing Plots in C# 394
Making Bar Plots 395
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Making Line Plots . 396
Consequences of the Strategy Pattern . 398
Programs on the CD-ROM . 398
30. The Template Method Pattern 399
Motivation . 399
Kinds of Methods in a Template Class . 401
Sample Code . 402
Drawing a Standard Triangle 404
Drawing an Isosceles Triangle 404
The Triangle Drawing Program 405
Templates and Callbacks 406
Summary and Consequences 407
Programs on the CD-ROM . 408
31. The Visitor Pattern . 409
Motivation . 409
When to Use the Visitor Pattern . 411
Sample Code . 411
Visiting the Classes . 413
Visiting Several Classes 414
Bosses Are Employees, Too . 416
Catch-All Operations with Visitors 417
Double Dispatching . 419
Why Are We Doing This? 419
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Traversing a Series of Classes 419
Consequences of the Visitor Pattern . 420
Thought Question 420
Programs on the CD-ROM . 421
32. Bibliography 422