C# Code Snippets

C# Code snippets / C# Examples / C# Samples

A C# code snippet is a brief example of useful C# source code or Visual C# source code. Sometimes called a recipe, a code snippet usually performs a single function. Being mere fragments of C# source code, the snippets often omit the required using statements. C# source code snippets are categorized alphabetically by namespace. Similar to a code gallery, place your fully functional C# methods in our C# source code bank—C# source code respository or C# cookbook—for all to share.

Contents 1 C# Code snippets / C# Examples / C# Samples 1.1 Microsoft.Win32 namespace 1.2 System namespace 1.3 System.Collections namespace 1.4 System.Collections.Generic namespace 1.5 System.Data.SqlClient namespace 1.6 System.DirectoryServices namespace 1.7 System.IO namespace 1.8 System.Management namespace 1.9 System.Media namespace 1.10 System.Net namespace 1.11 System.Reflection namespace 1.12 System.Runtime.InteropServices namespace 1.13 System.Security.Principal namespace 1.14 System.Text.RegularExpressions namespace 1.15 System.Threading namespace 1.16 System.Windows.Forms namespace 2 See also

Microsoft.Win32 namespace

• Read a Registry key - read a Windows Registry key.
• Write a Registry key - write a Windows Registry key.

System namespace

• Calculate Fibonacci number - recursion example calculates Fibonacci number.

• Calculate simple interest - calculate basic principal and interest on a simple loan.

• Calculate simple interest table - calculate basic principal and interest calculations on a simple loan over a period of years.

• Call with variable arguments - use params to implement a method with a variable number of arguments.

• Cast an object to an interface - access interface members as if they were members of the object.

• Catch an OverflowException - catch the exception caused by numeric overflow.

• Clear array values using Array.Clear - clear specified array values.

• Clone an array with Array.Clone - clone an entire array.

• Convert Fahrenheit and Celsius - convert temperatures between two scales.

• Copy an array with Array.Copy - copy all or part of an array to a second array.

• Copy one array into a second array with Array.CopyTo - copy an array to an index into a second array using the CopyTo method of the Array class.

• Create a MD5 Hash from a string - convert a string to a MD5 hash—a 32-character string of hexadecimal numbers.

• Create a multidimensional Array - create a multidimensional Array of a specified Type using Array.CreateInstance.

• Create and access a pointer array - create a pointer array of struct addresses and access them (unsafe code).

• Create and access a heterogeneous pointer array - create a pointer array of heterogeneous addresses and access them (unsafe code).

• Declare a constant - declare constants of all C# types using the const keyword.

• Declare a variable - declare variables of all C# types without initializing them.

• Declare a variable and assign a value - declare variables of all C# types without initializing them and assign values to them.

• Declare and initialize a variable - declare and initialize variables of all C# types.

• Declare multiline string literals - declare string literals which span multiple lines.

• Declare simple event - publish and subscribe a basic event.

• Demonstrate string methods - demonstrate various string methods.

• Format the date and time - display the various date and time formats.

• Get a number from the console - input a string a convert it to a number.

• Get a Type reference - obtain a Type reference to a given type.

• Get command line arguments - get the command line argument in Main.

• Get NetBIOS and DNS computer names - get the local computer name.

• Implement IDisposable interface - Implement IDisposable interface.

• Measure execution time - measure intervals and execution times.

• NightSky screen saver - a great project for beginning C# programmers.

• Overload the plus operator - overload the plus (+) operator to add objects.

• Override ToString method - override an object's inherited ToString method.

• Pass anonymous delegate - pass an anonymous delegate as an argument.

• Read Console input - read characters or strings from the Console.

• Reverse order of array elements - put the elements of an array in reverse order.

• Search array with binary search - conduct a binary search on an array.

• Sort array - sort the elements of an array.

• System.Exception - various C# exception handling examples.
  • System.Exception—catch an ArgumentException.
  • System.Exception—catch an ArgumentNullException.
  • System.Exception—catch an ArgumentOutOfRangeException.
  • System.Exception—catch an ArithmeticException.
  • System.Exception—catch an NotSupportedException.

• System.String - various C# string manipulation functions.
  • System.String—Find string length - determine the length of a string.

• Test for an interface implementation - test an object to determine if it implements a particular interface.

• Use enumerations - illustrates the declaration and use of enumerated types (enum keyword).

• Use enumerations as bit flags - illustrates the use of enumerated types (enum keyword) as bit flags.

System.Collections namespace

• Calculate prime numbers - find primes using a BitArray.

• Check ICollection Count property - find the number of elements in an array using ICollection.

• Check ICollection IsSynchronized property - test an ICollection to see if it is synchronized.

• Enumerate an array - enumerate over the elements of a multidimensional array using the IEnumerator interface.

• Set BitArray Value - Set the value of an instance of the BitArray class.

• Sort an array in reverse order - sort an array into descending order using the IComparer interface.

• System.Collections.IList interface - properties and methods.
  • Check IList IsFixedSize property - determine if an array has a fixed size using the IList interface.
  • Check IList IsReadOnly property - determine if an array is read only using the IList interface.
  • Check IList IsSynchronized property - determine if an array is synchronized using the IList interface.
  • Clear an array - clear array values using the Clear method of the IList interface.
  • Find common array values - find array values contained in a second array using the Contains method of the IList interface.
  • Iterate over an array using IList interface - iterate through array values using the Count property of the IList interface.

System.Collections.Generic namespace

• Create an indexer property - access a class like an array with an indexer.

System.Data.SqlClient namespace

• List SQL Server databases - display list of all SQL Server databases.

System.DirectoryServices namespace

• Create Group Object - create a Active Directory (AD) Group Object.

System.IO namespace

• Clear Internet Explorer cache - delete all Temporary Internet files.
• Create a directory - create (make) a folder (directory) on disk.
• Delete a directory - delete a folder (directory) from disk.
• Get directory creation time - get the creation time of the named directory.
• Get current directory path - get the current directory path as a string.
• List subdirectories - list all of the subdirectories of the current directory.
• Log messages to a file - log messages to a disk file for debugging or other logging purposes.
• Read a disk file - read a disk text file a line at a time.
• Write then read a text file - read and write a text file to disk.
• Test if directory exists - test whether a named folder (directory) exists on disk.

System.Management namespace

• Detect CD-ROM Insertion - detect if CD-ROM is inserted into the CD-ROM drive.

• CD-ROM Loaded - detect if a CD is already in the CD-ROM drive.

• Network Drive Free Space - Obtaining the free space of all network drives.

System.Media namespace

• Play default Windows sounds - play the standard Windows sounds from your application.

System.Net namespace

• HTTP Post - send an HTTP Post and get the response.

• System.Net.Mail - SMTP e-Mail functions.
  • Send an e-Mail - send out an e-Mail using SMTP.

• Invalid HTTPS certificate - ignore invalid HTTPS certificate (e.g., calling Web services).
• IP Address - get the IP address of the Host PC.

System.Reflection namespace

• Display Assembly attributes - list all the Assembly attributes in an assembly.
• Display type version number - display the version number of a given component.
• List Assembly exceptions - list the public exceptions from Assemblies.

System.Runtime.InteropServices namespace

• Create a C-style union - use ExplicitLayout to layout a struct in Visual C#.
• Empty the Recycle Bin - empty the Recycle Bin.
• Open/close CD drive tray - open and close the CD drive tray.

System.Security.Principal namespace

• Check if principal is Administrator - check if the current user is an Administrator.

System.Text.RegularExpressions namespace

• Check if all numeric string - returns true if string contains no alphabetic characters.
• Check if all upper case string - returns true if string contains no lower case characters.
• Parse connection string - finds the host name, instance name, and database name in the connection string.
• Strip all HTML tags - removes all HTML tags from the input string.

System.Threading namespace

• Check current thread priority - get the Priority property of the current thread.
• Check if current thread is a thread pool thread - test IsThreadPoolThread property of the current thread.
• Check if current thread is alive - test the IsAlive property of the current thread.
• Check if current thread is background thread - test the IsBackground property of the current thread.
• Check the state of the current thread - get the ThreadState property of the current thread.
• Get current thread name - get the Name property of the current thread.
• Set current thread name - set the Name property of the current thread.
• Use the TimerCallback delegate - the TimerCallback delegate is used for periodic call backs.

System.Windows.Forms namespace

• Pick a color with ColorDialog - select a color using the ColorDialog dialog box.

• Select a file with OpenFileDialog - pick a file using the OpenFileDialog dialog box.

• Set a control font with FontDialog - set the font in a control with ColorDialog.

• Retrieve the current screen resolution - get the screen resolution using the SystemInformation class.

See also

• Visual Studio Code Snippets