How to convert PascalCase to kebab-case with C #?

Question

How to convert string value in PascalCase (another name is UpperCamelCase) in kebab-case with C #?

eg. "VeryLongName" to "very-long-name"

Answer 1

Here's how to do it with regex:

 public static class StringExtensions { public static string PascalToKebabCase(this string value) { if (string.IsNullOrEmpty(value)) return value; return Regex.Replace( value, "(?<!^)([AZ][az]|(?<=[az])[AZ])", "-$1", RegexOptions.Compiled) .Trim() .ToLower(); } } 

Answer 2

Here is a way to do this without using Regex:

 public static string PascalToKebabCase(this string str) { if (string.IsNullOrEmpty(str)) return string.Empty; var builder = new StringBuilder(); builder.Append(char.ToLower(str.First())); foreach (var c in str.Skip(1)) { if (char.IsUpper(c)) { builder.Append('-'); builder.Append(char.ToLower(c)); } else { builder.Append(c); } } return builder.ToString(); } 

You will have problems with known abbreviations that use uppercase letters. For example: COMObject . This solution obviously did not work.

Answer 3

Here is my solution using Microsoft's capitalization conventions. https://docs.microsoft.com/en-us/dotnet/standard/design-guidelines/capitalization-conventions

 public static class StringExtensions { public static string ToKebabCase(this string source) { if (source is null) return null; if(source.Length == 0) return string.Empty; StringBuilder builder = new StringBuilder(); for(var i = 0; i < source.Length; i++) { if (char.IsLower(source[i])) // if current char is already lowercase { builder.Append(source[i]); } else if(i == 0) // if current char is the first char { builder.Append(char.ToLower(source[i])); } else if (char.IsLower(source[i - 1])) // if current char is upper and previous char is lower { builder.Append("-"); builder.Append(char.ToLower(source[i])); } else if(i + 1 == source.Length || char.IsUpper(source[i + 1])) // if current char is upper and next char doesn't exist or is upper { builder.Append(char.ToLower(source[i])); } else // if current char is upper and next char is lower { builder.Append("-"); builder.Append(char.ToLower(source[i])); } } return builder.ToString(); } } 

Test

 string[] stringArray = new[] { null, "", "I", "IO", "FileIO", "SignalR", "IOStream", "COMObject", "WebAPI" }; foreach (var str in stringArray) { Console.WriteLine($"{str} --> {str.ToKebabCase()}"); } // Output: // --> // --> // I --> i // IO --> io // FileIO --> file-io // SignalR --> signal-r // IOStream --> io-stream // COMObject --> com-object // WebAPI --> web-api