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Extension Methods Library

09 Jan 2014

Extension methods are a compiler trick which allows static methods to be called using instance methods syntax. They are so convenient that LINQ is essentially a collection of extension methods. Extension methods are a good way to shrink your code and follow the DRY principle. For example, instead of the following long code

bool IsValidOs(string os)
{
    return os.Equals("Windows", StringComparison.OrdinalIgnoreCase) ||
           os.Equals("Linux", StringComparison.OrdinalIgnoreCase) ||
           os.Equals("Mac OS", StringComparison.OrdinalIgnoreCase);
}

The following version is much more readable:

bool IsValidOs(string os)
{
    return os.IsLikeAny("Windows", "Linux", "Mac OS");
}

I have been using several extension methods in my code for a while, but then I decided to share them with the world.

To add the library to your project, open Package Manager Console, select your project and type

Install-Package ExtensionMethods

Install-Package ExtensionMethods

Import the namespace

using ExtensionMethods;

Here is a list of the included methods:

ToFormat()

Similar to string.Format

"My name is {0} {1}".ToFormat("Nadeem", "Afana");  // My name is Nadeem Afana

You can even use it on nullable types:

int? value = 12700;
value.ToFormat("#,#"); // 12,700 
     
value = null;
value.ToFormat("#,#"); // null

ToFormatNamed() (Deprecated)

Note: Use C# 6 interpolated strings.

Similar to string.Format but uses named formats for better readability.

string firstName = "Nadeem";
string lastName = "Afana";
string language = "C#";
"My name is {first} {last}, and I like {lang}.".ToFormatNamed(firstName, lastName, language); 
// My name is Nadeem Afana, and I like C#.

It also supports composite formatting:

int kbps = 30000;
  
@"The day is {dayName:dddd} and the time is {hour:hh:mm}. 
The Internet speed is {speed:#.0} mbps.
".ToFormatNamed(DateTime.Now, DateTime.Now, kbps/1000.0);
// The day is Sunday and the time is 05:31. The Internet speed is 30.0 mbps.

The variable names do not have to match the arguments,but the order of arguments is important.

Reverse()

Reverses a string.

"The quick brown fox jumps over the lazy dog".Reverse();
// god yzal eht revo spmuj xof nworb kciuq ehT

Left()

Reads the first n characters from the left of a string.

"The quick brown fox jumps over the lazy dog".Left(9);
// The quick

Reads the first n characters from the right of a string.

"The quick brown fox jumps over the lazy dog".Right(3);
// dog

IsLike()

Determines whether two strings have the same value ignoring Case.

"STRING".IsLike("String"); // True

IsLikeAny()

Determines whether a string matches any value in a collection of strings ignoring case.

"c#".IsLikeAny("C++", "C#", "VB");  // True

IsLikeAll()

Determines whether a string matches all the values in a collection of strings ignoring case.

"internet".IsLikeAll("Internet", "INTERNET", "iNTerNet");  // True

StartsLike()

Determines whether the beginning of a string matches the specified string ignoring case.

string s = "The quick brown fox jumps over the lazy dog";
s.StartsLike("the"); // True

EndsLike()

Determines whether the end of a string matches the specified string ignoring case.

string s = "The quick brown fox jumps over the lazy dog";
s.EndsLike("DOG"); // True

TrimStart()

Removes a string from the beginning of another string.

string s = "The quick brown fox jumps over the lazy dog";
s.TrimStart("The"); //  quick brown fox jumps over the lazy dog
 
s.TrimStart("THE", false); // case insensitive
//  quick brown fox jumps over the lazy dog

TrimEnd()

Removes a string from the end of another string.

string s = "The quick brown fox jumps over the lazy dog";
s.TrimEnd("dog"); 
// The quick brown fox jumps over the lazy 
s.TrimEnd("DOG", false); // case insensitive
// The quick brown fox jumps over the lazy

Capitalize()

Capitalizes the first letter of each word. Synonym for ToTitleCase()

string s = "the internet";
s.Capitalize(); // The Internet

ToTitleCase()

Capitalizes the first letter of each word. Synonym for Capitalize()

string s = "the internet";
s.ToTitleCase(); // The Internet

IsNullOrWhiteSpace()

Indicates whether a specified string is null, empty, or consists only of white-space characters.

string s = "       ";
s.IsNullOrWhiteSpace(); // True
 
s = null;
s.IsNullOrWhiteSpace(); // True
 
s = string.Empty;
s.IsNullOrWhiteSpace(); // True

IsNumeric()

Determines if a string can be parsed into a number.

"1253".IsNumeric(); // True
 
"Abc".IsNumeric(); // False

ToBase64()

Converts a string into Base64 encoding.

string s = "Hello World!";
s.ToBase64(); // SGVsbG8gV29ybGQh   (Utf8)
 
s.ToBase64(Encoding.UTF32); // Utf32 
// SAAAAGUAAABsAAAAbAAAAG8AAAAgAAAAVwAAAG8AAAByAAAAbAAAAGQAAAAhAAAA

FromBase64()

Decodes a Base64-encoded string.

"SGVsbG8gV29ybGQh".FromBase64(); // Hello World!   (Utf8)
 
"SAAAAGUAAABsAAAAbAAAAG8AAAAgAAAAVwAAAG8AAAByAAAAbAAAAGQAAAAhAAAA".FromBase64(Encoding.UTF32); // Hello World! (Utf32)

ToMd5()

Computes MD5 hash of a string.

"Hello World!".ToMd5(); // ed076287532e86365e841e92bfc50d8c (Utf8)
 
"Hello World!".ToMd5(Encoding.UTF32); // b090a014200184a82c6fff39816cb5bc (Utf32)

ToBytes()

Converts a string into an array of bytes.

"Hello World!".ToBytes(); // Utf8
// { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33};
 
"Hello World!".ToBytes(Encoding.UTF7);  // Utf7
// { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 43, 65, 67, 69, 45};

ToInt()

Parses an integer from a string.

"1500".ToInt(); // 1500

ToIntOrDefault()

Parses an integer from a string. If parsing fails, returns a default integer.

"1500".ToIntOrDefault(); // 1500
"Abc".ToIntOrDefault(0); // 0

ToDouble()

Parses a double from a string.

"3.14".ToDouble(); // 3.14

ToDoubleOrDefault()

Parses a double from a string. If parsing fails, returns a default double value.

"3.14".ToDoubleOrDefault(); // 3.14
"Abc".ToDoubleOrDefault(0.0); // 0.0

Scans a string for valid http Urls and converts them to Html links.

"My website is www.afana.me".ToLink();  
// My website is <a href="http://www.afana.me/">www.afana.me</a>
 
"My website is www.afana.me".ToLink("click here"); 
// My website is <a href="http://www.afana.me/">click here</a>

ContainsAny()

Determines whether a string contains at least one of the specified strings.

string s = "The quick brown fox jumps over the lazy dog";
s.ContainsAny("a", "fox"); // True

ContainsAll()

Determines whether a string contains all the specified strings.

string s = "The quick brown fox jumps over the lazy dog";
s.ContainsAll("dog", "fox"); // True

bool.ToYesOrNo()

Returns Yes or No string if a boolean value is true or false, respectively. This can be very useful especially in MVC views.

bool isOpen = true;
"Is Open: {0}".ToFormat(isOpen.ToYesOrNo()); // Is Open: Yes

bytes[].ToHexString()

Converts a collection of bytes into hexadecimal string respresentation.

byte[] bytes = new byte[] { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33 };
bytes.ToHexString(); // 48656c6c6f20576f726c6421

IPrincipal.GetUserNameOnly()

Returns the user name without a domain name.

Thread.CurrentPrincipal.GetUserNameOnly(); // Domain\Nadeem => Nadeem

IPrincipal.IsInAnyRole()

Determines if a IPrincipal belongs to at least one of the specified roles.

var user = Thread.CurrentPrincipal; 
user.IsInAnyRole("admin", "user");

IPrincipal.IsInAllRoles()

Determines if a IPrincipal belongs to all the specified roles.

var user = Thread.CurrentPrincipal; 
user.IsInAllRoles("admin", "db_admin");

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