C# Cookbook
暫譯: C# 食譜

Easy to learn and use, the C# language is targeted at developers for Microsoft's .NET platform who've worked with a C-like language before, such as C, C++, or Java. There's no shortage of excellent tutorials and documentation to help new developers get a handle on the language, such as O'Reilly's Learning C# or Programming C#. But when you need practical answers to the day-to-day questions you run up against, a tutorial isn't going to do the trick. The C# Cookbook gets straight to the heart of the problem with code recipes collected especially for developers working on the .NET platform.

The C# Cookbook offers a definitive collection of solutions and examples for this new programming language. Recipes range from simple tasks to the more complex, and are organized with respect to the types of problems you'll need to solve as you progress in your experience as a C# programmer. Nearly every recipe contains a complete, documented code sample showing you how to solve the specific problem, as well as a discussion of how the underlying technology works and a discussion of alternatives, limitations, and other considerations where appropriate.

The recipes in the C# Cookbook are organized into seventeen chapters, each of which focuses on a particular topic in creating C# solutions. Among the topics covered, you'll find:

• Numeric data types in C#
  
• Strings and characters
  
• Classes and structures
  
• Exception handling
  
• Delegates and events
  
• Regular expressions
  
• Data structures and algorithms
  
• Networking
  
• Security
  
• Unsafe Code

You don't need to be an experienced C# or .NET developer to use this book. The C# Cookbook is designed for users of all levels with recipes targeted at the real-world developer who needs to solve problems now, not learn lots of theory first. With this guide, all developers will be able to learn and improve their mastery of both the language and the .NET Framework Class Libraries.

Table of Contents

Preface 

1. Numbers

       1.1 Determining Approximate Equality Between a Fraction and Floating-Point Value   

       1.2 Converting Degrees to Radians   

       1.3 Converting Radians to Degrees   

       1.4 Using the Bitwise Complement Operator with Various Data Types   

       1.5 Test for an Even or Odd Value   

       1.6 Obtaining the Most- or Least-Significant Bits of a Number   

       1.7 Converting a Number in Another Base to Base10   

       1.8 Determining Whether a String Is a Valid Number   

       1.9 Rounding a Floating-Point Value   

       1.10 Different Rounding Algorithms   

       1.11 Converting Celsius to Fahrenheit   

       1.12 Converting Fahrenheit to Celsius   

       1.13 Safely Performing a Narrowing Numeric Cast   

       1.14 Finding the Length of Any Three Sides of a Right Triangle   

       1.15 Finding the Angles of a Right Triangle   

2. Strings and Characters

       2.1 Determining the Kind of Character   

       2.2 Determining Whether a Character Is Within a Specified Range   

       2.3 Controlling Case Sensitivity when Comparing Two Characters   

       2.4 Finding All Occurrences of a Character Within a String   

       2.5 Finding the Location of All Occurrences of a String WithinAnother String   

       2.6 The Poor Man's Tokenizer   

       2.7 Controlling Case Sensitivity when Comparing Two Strings   

       2.8 Comparing a String to the Beginning or End of a Second String   

       2.9 Inserting Text into a String   

       2.10 Removing or Replacing Characters Within a String

       2.11 Encoding Binary Data as Base64   

       2.12 Decoding a Base64-Encoded Binary   

       2.13 Converting a String Returned as a Byte[ ] Back into a String   

       2.14 Passing a String to a Method that Accepts Only a Byte[ ]   

       2.15 Converting Strings to Their Equivalent Value Type   

       2.16 Formatting Data in Strings   

       2.17 Creating a Delimited String   

       2.18 Extracting Items from a Delimited String   

       2.19 Setting the Maximum Number of Characters a String Can Contain   

       2.20 Iterating Over Each Character in a String   

       2.21 Improving String Comparison Performance   

       2.22 Improving StringBuilder Performance   

       2.23 Pruning Characters from the Head and/or Tail of a String   

3. Classes and Structures

       3.1 Creating Union-Type Structures   

       3.2 Allowing a Type to Represent Itself as a String  

       3.3 Converting a String Representation of an Object into an Actual Object   

       3.4 Polymorphism via Concrete or Abstract Base Classes   

       3.5 Making a Type Sortable   

       3.6 Making a Type Searchable   

       3.7 Indirectly Overloading the +=, -=, /=, and *= Operators   

       3.8 Indirectly Overloading the &&, ||, and ?: Operators   

       3.9 Improving the Performance of a Structure's Equals Method   

       3.10 Turning Bits On or Off   

       3.11 Making Error-Free Expressions   

       3.12 Minimizing (Reducing) Your Boolean Logic   

       3.13 Converting Between Simple Types in a Language Agnostic Manner   

       3.14 Determining Whether to Use the Cast Operator, the as Operator, or the is Operator

       3.15 Casting with the as Operator   

       3.16 Determining a Variable's Type with the is Operator   

       3.17 Polymorphism via Interfaces   

       3.18 Calling the Same Method on Multiple Object Types   

       3.19 Adding a Notification Callback Using an Interface   

       3.20 Using Multiple Entry Points to Version an Application   

       3.21 Preventing the Creation of an Only Partially Initialized Object   

       3.22 Returning Multiple Items from a Method   

       3.23 Parsing Command-Line Parameters   

       3.24 Retrofitting a Class to Interoperate with COM   

       3.25 Initializing a Constant Field at Runtime   

       3.26 Writing Code that Is Compatible with the Widest Rangeof Managed Languages   

       3.27 Implementing Nested foreach Functionality in a Class   

       3.28 Building Cloneable Classes   

       3.29 Assuring an Object's Disposal   

       3.30 Releasing a COM Object Through Managed Code   

       3.31 Creating an Object Cache   

       3.32 The Single Instance Object   

       3.33 Choosing a Serializer   

       3.34 Creating Custom Enumerators   

       3.35 Rolling Back Object Changes   

       3.36 Disposing of Unmanaged Resources   

       3.37 Determining Where Boxing and Unboxing Occur   

4. Enumerations

       4.1 Displaying an Enumeration Value as a String   

       4.2 Converting Plain Text to an Equivalent Enumeration Value   

       4.3 Testing for a Valid Enumeration Value   

       4.4 Testing for a Valid Enumeration of Flags   

       4.5 Using Enumerated Members in a Bitmask   

       4.6 Determining Whether One or More Enumeration Flags Are Set   

5. Exception Handling

       5.1 Verifying Critical Parameters   

       5.2 Indicating Where Exceptions Originate   

       5.3 Choosing when to Throw a Particular Exception   

       5.4 Handling Derived Exceptions Individually   

       5.5 Assuring Exceptions are Not Lost when Using Finally Blocks   

       5.6 Handling Exceptions Thrown from Methods Invoked via Reflection   

       5.7 Debugging Problems when Loading an Assembly   

       5.8 HRESULT-Exception Mapping   

       5.9 Handling User-Defined HRESULTs   

       5.10 Preventing Unhandled Exceptions   

       5.11 Displaying Exception Information   

       5.12 Getting to the Root of a Problem Quickly   

       5.13 Creating a New Exception Type   

       5.14 Obtaining a Stack Trace   

       5.15 Breaking on a First Chance Exception   

       5.16 Preventing the Nefarious TypeInitializationException   

       5.17 Handling Exceptions Thrown from an Asynchronous Delegate   

6. Diagnostics

       6.1 Controlling Tracing Output in Production Code   

       6.2 Providing Fine-Grained Control Over Debugging/Tracing Output   

       6.3 Creating Your Own Custom Switch Class   

       6.4 A Custom Trace Class that Outputs Information in an XML Format   

       6.5 Conditionally Compiling Blocks of Code   

       6.6 Determining Whether a Process Has Stopped Responding   

       6.7 Using One or More Event Logs in Your Application   

       6.8 Changing the Maximum Size of a Custom Event Log   

       6.9 Searching Event Log Entries   

       6.10 Watching the Event Log for a Specific Entry   

       6.11 Finding All Sources Belonging to a Specific Event Log   

       6.12 Implementing a Simple Performance Counter   

       6.13 Implementing Performance Counters that Require a Base Counter   

       6.14 Enable/Disable Complex Tracing Code   

7. Delegates and Events

       7.1 Controlling when and if a Delegate Fires Within a Multicast Delegate   

       7.2 Obtaining Return Values from Each Delegate in a Multicast Delegate 

       7.3 Handling Exceptions Individually for Each Delegate in a Multicast Delegate   

       7.4 Converting a Synchronous Delegate to an Asynchronous Delegate   

       7.5 Adding Events to a Sealed Class   

       7.6 Passing Specialized Parameters to and from an Event   

       7.7 An Advanced Interface Search Mechanism   

       7.8 An Advanced Member Search Mechanism   

       7.9 Observing Additions and Modifications to a Hashtable   

       7.10 Using the Windows Keyboard Hook   

       7.11 Using Windows Hooks to Manipulate the Mouse   

8. Regular Expressions

       8.1 Enumerating Matches   

       8.2 Extracting Groups from a MatchCollection   

       8.3 Verifying the Syntax of a Regular Expression   

       8.4 Quickly Finding Only the Last Match in a String   

       8.5 Replacing Characters or Words in a String   

       8.6 Augmenting the Basic String Replacement Function   

       8.7 A Better Tokenizer   

       8.8 Compiling Regular Expressions   

       8.9 Counting Lines of Text   

       8.10 Returning the Entire Line in Which a Match Is Found   

       8.11 Finding a Particular Occurrence of a Match   

       8.12 Using Common Patterns   

       8.13 Documenting Your Regular Expressions   

9. Collections

       9.1 Swapping Two Elements in an Array   

       9.2 Quickly Reversing an Array   

       9.3 Reversing a Two-Dimensional Array   

       9.4 Reversing a Jagged Array   

       9.5 A More Flexible StackTrace Class   

       9.6 Determining the Number of Times an Item Appears in an ArrayList   

       9.7 Retrieving All Instances of a Specific Item in an ArrayList   

       9.8 Inserting and Removing Items from an Array   

       9.9 Keeping Your ArrayList Sorted   

       9.10 Sorting a Hashtable's Keys and/or Values   

       9.11 Creating a Hashtable with Max and Min Size Boundaries   

       9.12 Creating a Hashtable with Max and Min Value Boundaries   

       9.13 Displaying an Array's Data as a Delimited String   

       9.14 Storing Snapshots of Lists in an Array   

       9.15 Creating a Strongly Typed Collection   

       9.16 Persisting a Collection Between Application Sessions   

10. Data Structures and Algorithms

       10.1 Creating a Hash Code for a Data Type   

       10.2 Creating a Priority Queue   

       10.3 Creating a More Versatile Queue   

       10.4 Determining Where Characters or Strings Do Not Balance   

       10.5 Creating a One-to-Many Map (MultiMap)   

       10.6 Creating a Binary Tree   

       10.7 Creating an n-ary Tree   

       10.8 Creating a Set Object   

11. Filesystem I/O

       11.1 Creating, Copying, Moving, and Deleting a File   

       11.2 Manipulating File Attributes   

       11.3 Renaming a File   

       11.4 Determining Whether a File Exists   

       11.5 Choosing a Method of Opening a File or Stream for Reading and/or Writing   

       11.6 Randomly Accessing Part of a File   

       11.7 Outputting a Platform-Independent EOL Character   

       11.8 Create, Write to, and Read from a File   

       11.9 Determining Whether a Directory Exists   

       11.10 Creating, Moving, and Deleting a Directory   

       11.11 Manipulating Directory Attributes   

       11.12 Renaming a Directory   

       11.13 Searching for Directories or Files Using Wildcards   

       11.14 Obtaining the Directory Tree   

       11.15 Parsing a Path   

       11.16 Parsing Paths in Environment Variables   

       11.17 Verifying a Path   

       11.18 Using a Temporary File in Your Application   

       11.19 Opening a File Stream with just a File Handle   

       11.20 Write to Multiple Output Files at One Time   

       11.21 Launching and Interacting with Console Utilities   

       11.22 Locking Subsections of a File   

       11.23 Watching the Filesystem for Specific Changes to One or MoreFiles or Directories   

       11.24 Waiting for an Action to Occur in the Filesystem   

       11.25 Comparing Version Information of Two Executable Modules   

12. Reflection

       12.1 Listing Imported Assemblies   

       12.2 Listing Exported Types   

       12.3 Finding Overridden Methods   

       12.4 Finding Members in an Assembly   

       12.5 Finding Members Within an Interface   

       12.6 Obtaining Types Nested Within a Type   

       12.7 Displaying the Inheritance Hierarchy for a Type   

       12.8 Finding the Subclasses of a Type   

       12.9 Finding All Serializable Types Within an Assembly   

       12.10 Controlling Additions to an ArrayList Through Attributes   

       12.11 Filtering Output when Obtaining Members   

       12.12 Dynamically Invoking Members   

13. Networking

       13.1 Converting an IP Address to a Hostname   

       13.2 Converting a Hostname to an IP Address   

       13.3 Parsing a URI   

       13.4 Forming an Absolute URI   

       13.5 Handling Web Server Errors   

       13.6 Communicating with a Web Server   

       13.7 Going Through a Proxy   

       13.8 Obtaining the HTML from a URL   

       13.9 Writing a TCP Server   

       13.10 Writing a TCP Client   

       13.11 Simulating Form Execution   

       13.12 Downloading Data from a Server   

       13.13 Using Named Pipes to Communicate   

14. Security

       14.1 Controlling Access to Types in a Local Assembly   

       14.2 Encrypting/Decrypting a String   

       14.3 Encrypting and Decrypting a File   

       14.4 Cleaning Up Cryptography Information   

       14.5 Verifying that a String Is Uncorrupted During Transmission   

       14.6 Wrapping a String Hash for Ease of Use   

       14.7 A Better Random Number Generator   

       14.8 Securely Storing Data   

       14.9 Making a Security Assert Safe   

       14.10 Preventing Malicious Modifications to an Assembly   

       14.11 Verifying that an Assembly Has Been Granted Specific Permissions 

       14.12 Minimizing the Attack Surface of an Assembly   

15. Threading

       15.1 Creating Per-Thread Static Fields   

       15.2 Providing Thread Safe Access to Class Members   

       15.3 Preventing Silent Thread Termination   

       15.4 Polling an Asynchronous Delegate   

       15.5 Timing Out an Asynchronous Delegate   

       15.6 Being Notified of the Completion of an Asynchronous Delegate   

       15.7 Waiting for Worker Thread Completion   

       15.8 Synchronizing the Reading and Writing of a Resource Efficiently   

       15.9 Determining Whether a Request for a Pooled ThreadWill Be Queued   

       15.10 Waiting for All Threads in the Thread Pool to Finish   

       15.11 Configuring a Timer   

       15.12 Storing Thread-Specific Data Privately   

16. Unsafe Code

       16.1 Controlling Changes to Pointers Passed to Methods   

       16.2 Comparing Pointers   

       16.3 Navigating Arrays   

       16.4 Manipulating a Pointer to a Fixed Array   

       16.5 Returning a Pointer to a Particular Element in an Array   

       16.6 Creating and Using an Array of Pointers   

       16.7 Creating and Using an Array of Pointers to Unknown Types   

       16.8 Switching Unknown Pointer Types   

       16.9 Breaking Up Larger Numbers into Their Equivalent Byte Array Representation   

       16.10 Converting Pointers to a Byte[], SByte[], or Char[] to a String  

17. XML

       17.1 Reading and Accessing XML Data in Document Order   

       17.2 Reading XML on the Web   

       17.3 Querying the Contents of an XML Document   

       17.4 Validating XML   

       17.5 Creating an XML Document Programmatically   

       17.6 Detecting Changes to an XML Document   

       17.7 Handling Invalid Characters in an XML String   

       17.8 Transforming XML to HTML   

       17.9 Tearing Apart an XML Document   

       17.10 Putting Together an XML Document   

Index