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Splitting CamelCase

Posted by: admin November 30, 2017 Leave a comment

Questions:

This is all asp.net c#.

I have an enum

public enum ControlSelectionType 
{
    NotApplicable = 1,
    SingleSelectRadioButtons = 2,
    SingleSelectDropDownList = 3,
    MultiSelectCheckBox = 4,
    MultiSelectListBox = 5
}

The numerical value of this is stored in my database. I display this value in a datagrid.

<asp:boundcolumn datafield="ControlSelectionTypeId" headertext="Control Type"></asp:boundcolumn>

The ID means nothing to a user so I have changed the boundcolumn to a template column with the following.

<asp:TemplateColumn>
    <ItemTemplate>
        <%# Enum.Parse(typeof(ControlSelectionType), DataBinder.Eval(Container.DataItem, "ControlSelectionTypeId").ToString()).ToString()%>
    </ItemTemplate>
</asp:TemplateColumn>

This is a lot better… However, it would be great if there was a simple function I can put around the Enum to split it by Camel case so that the words wrap nicely in the datagrid.

Note: I am fully aware that there are better ways of doing all this. This screen is purely used internally and I just want a quick hack in place to display it a little better.

Answers:

Indeed a regex/replace is the way to go as described in the other answer, however this might also be of use to you if you wanted to go a different direction

    using System.ComponentModel;
    using System.Reflection;

    public static string GetDescription(System.Enum value)
    {
        FieldInfo fi = value.GetType().GetField(value.ToString());
        DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
        if (attributes.Length > 0)
            return attributes[0].Description;
        else
            return value.ToString();
    }

this will allow you define your Enums as

public enum ControlSelectionType 
{
    [Description("Not Applicable")]
    NotApplicable = 1,
    [Description("Single Select Radio Buttons")]
    SingleSelectRadioButtons = 2,
    [Description("Completely Different Display Text")]
    SingleSelectDropDownList = 3,
}

Taken from

http://www.codeguru.com/forum/archive/index.php/t-412868.html

Questions:
Answers:

I used:

    public static string SplitCamelCase(string input)
    {
        return System.Text.RegularExpressions.Regex.Replace(input, "([A-Z])", " $1", System.Text.RegularExpressions.RegexOptions.Compiled).Trim();
    }

Taken from http://weblogs.asp.net/jgalloway/archive/2005/09/27/426087.aspx

Questions:
Answers:

If C# 3.0 is an option you can use the following one-liner to do the job:


Regex.Matches(YOUR_ENUM_VALUE_NAME, "[A-Z][a-z]+").OfType<Match>().Select(match => match.Value).Aggregate((acc, b) => acc + " " + b).TrimStart(' ');

Questions:
Answers:

This regex (^[a-z]+|[A-Z]+(?![a-z])|[A-Z][a-z]+) can be used to extract all words from the camelCase or PascalCase name. It also works with abbreviations anywhere inside the name.

  • MyHTTPServer will contain exactly 3 matches: My, HTTP, Server
  • myNewXMLFile will contain 4 matches: my, New, XML, File

You could then join them into a single string using string.Join.

string name = "myNewUIControl";
string[] words = Regex.Matches(name, "(^[a-z]+|[A-Z]+(?![a-z])|[A-Z][a-z]+)")
    .OfType<Match>()
    .Select(m => m.Value)
    .ToArray();
string result = string.Join(" ", words);

Questions:
Answers:

Here’s an extension method that handles numbers and multiple uppercase characters sanely, and also allows for upper-casing specific acronyms in the final string:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;
using System.Text.RegularExpressions;
using System.Web.Configuration;

namespace System
{
    /// <summary>
    /// Extension methods for the string data type
    /// </summary>
    public static class ConventionBasedFormattingExtensions
    {
        /// <summary>
        /// Turn CamelCaseText into Camel Case Text.
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        /// <remarks>Use AppSettings["SplitCamelCase_AllCapsWords"] to specify a comma-delimited list of words that should be ALL CAPS after split</remarks>
        /// <example>
        /// wordWordIDWord1WordWORDWord32Word2
        /// Word Word ID Word 1 Word WORD Word 32 Word 2
        /// 
        /// wordWordIDWord1WordWORDWord32WordID2ID
        /// Word Word ID Word 1 Word WORD Word 32 Word ID 2 ID
        /// 
        /// WordWordIDWord1WordWORDWord32Word2Aa
        /// Word Word ID Word 1 Word WORD Word 32 Word 2 Aa
        /// 
        /// wordWordIDWord1WordWORDWord32Word2A
        /// Word Word ID Word 1 Word WORD Word 32 Word 2 A
        /// </example>
        public static string SplitCamelCase(this string input)
        {
            if (input == null) return null;
            if (string.IsNullOrWhiteSpace(input)) return "";

            var separated = input;

            separated = SplitCamelCaseRegex.Replace(separated, @" $1").Trim();

            //Set ALL CAPS words
            if (_SplitCamelCase_AllCapsWords.Any())
                foreach (var word in _SplitCamelCase_AllCapsWords)
                    separated = SplitCamelCase_AllCapsWords_Regexes[word].Replace(separated, word.ToUpper());

            //Capitalize first letter
            var firstChar = separated.First(); //NullOrWhiteSpace handled earlier
            if (char.IsLower(firstChar))
                separated = char.ToUpper(firstChar) + separated.Substring(1);

            return separated;
        }

        private static readonly Regex SplitCamelCaseRegex = new Regex(@"
            (
                (?<=[a-z])[A-Z0-9] (?# lower-to-other boundaries )
                |
                (?<=[0-9])[a-zA-Z] (?# number-to-other boundaries )
                |
                (?<=[A-Z])[0-9] (?# cap-to-number boundaries; handles a specific issue with the next condition )
                |
                (?<=[A-Z])[A-Z](?=[a-z]) (?# handles longer strings of caps like ID or CMS by splitting off the last capital )
            )"
            , RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace
        );

        private static readonly string[] _SplitCamelCase_AllCapsWords =
            (WebConfigurationManager.AppSettings["SplitCamelCase_AllCapsWords"] ?? "")
                .Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries)
                .Select(a => a.ToLowerInvariant().Trim())
                .ToArray()
                ;

        private static Dictionary<string, Regex> _SplitCamelCase_AllCapsWords_Regexes;
        private static Dictionary<string, Regex> SplitCamelCase_AllCapsWords_Regexes
        {
            get
            {
                if (_SplitCamelCase_AllCapsWords_Regexes == null)
                {
                    _SplitCamelCase_AllCapsWords_Regexes = new Dictionary<string,Regex>();
                    foreach(var word in _SplitCamelCase_AllCapsWords)
                        _SplitCamelCase_AllCapsWords_Regexes.Add(word, new Regex(@"\b" + word + @"\b", RegexOptions.Compiled | RegexOptions.IgnoreCase));
                }

                return _SplitCamelCase_AllCapsWords_Regexes;
            }
        }
    }
}

Questions:
Answers:

Tillito’s answer does not handle strings already containing spaces well, or Acronyms. This fixes it:

public static string SplitCamelCase(string input)
{
    return Regex.Replace(input, "(?<=[a-z])([A-Z])", " $1", RegexOptions.Compiled);
}

Questions:
Answers:
public enum ControlSelectionType    
{   
    NotApplicable = 1,   
    SingleSelectRadioButtons = 2,   
    SingleSelectDropDownList = 3,   
    MultiSelectCheckBox = 4,   
    MultiSelectListBox = 5   
} 
public class NameValue
{
    public string Name { get; set; }
    public object Value { get; set; }
}    
public static List<NameValue> EnumToList<T>(bool camelcase)
        {
            var array = (T[])(Enum.GetValues(typeof(T)).Cast<T>()); 
            var array2 = Enum.GetNames(typeof(T)).ToArray<string>(); 
            List<NameValue> lst = null;
            for (int i = 0; i < array.Length; i++)
            {
                if (lst == null)
                    lst = new List<NameValue>();
                string name = "";
                if (camelcase)
                {
                    name = array2[i].CamelCaseFriendly();
                }
                else
                    name = array2[i];
                T value = array[i];
                lst.Add(new NameValue { Name = name, Value = value });
            }
            return lst;
        }
        public static string CamelCaseFriendly(this string pascalCaseString)
        {
            Regex r = new Regex("(?<=[a-z])(?<x>[A-Z])|(?<=.)(?<x>[A-Z])(?=[a-z])");
            return r.Replace(pascalCaseString, " ${x}");
        }

//In  your form 
protected void Button1_Click1(object sender, EventArgs e)
        {
            DropDownList1.DataSource = GeneralClass.EnumToList<ControlSelectionType  >(true); ;
            DropDownList1.DataTextField = "Name";
            DropDownList1.DataValueField = "Value";

            DropDownList1.DataBind();
        }

Questions:
Answers:

The solution from Eoin Campbell works good except if you have a Web Service.

You would need to do the Following as the Description Attribute is not serializable.

[DataContract]
public enum ControlSelectionType
{
    [EnumMember(Value = "Not Applicable")]
    NotApplicable = 1,
    [EnumMember(Value = "Single Select Radio Buttons")]
    SingleSelectRadioButtons = 2,
    [EnumMember(Value = "Completely Different Display Text")]
    SingleSelectDropDownList = 3,
}


public static string GetDescriptionFromEnumValue(Enum value)
{
    EnumMemberAttribute attribute = value.GetType()
        .GetField(value.ToString())
        .GetCustomAttributes(typeof(EnumMemberAttribute), false)
        .SingleOrDefault() as EnumMemberAttribute;
    return attribute == null ? value.ToString() : attribute.Value;
}

Questions:
Answers:

You can use C# extension methods

        public static string SpacesFromCamel(this string value)
        {
            if (value.Length > 0)
            {
                var result = new List<char>();
                char[] array = value.ToCharArray();
                foreach (var item in array)
                {
                    if (char.IsUpper(item))
                    {
                        result.Add(' ');
                    }
                    result.Add(item);
                }

                return new string(result.ToArray());
            }
            return value;
        }

Then you can use it like

var result = "TestString".SpacesFromCamel();

Result will be

Test String

Questions:
Answers:

Using LINQ:

var chars = ControlSelectionType.NotApplicable.ToString().SelectMany((x, i) => i > 0 && char.IsUpper(x) ? new char[] { ' ', x } : new char[] { x });

Console.WriteLine(new string(chars.ToArray()));

Questions:
Answers:

And if you don’t fancy using regex – try this:

public static string SeperateByCamelCase(this string text, char splitChar = ' ') {

        var output = new StringBuilder();

        for (int i = 0; i < text.Length; i++)
        {
            var c = text[i];

            //if not the first and the char is upper
            if (i > 0 && char.IsUpper(c)) {

                var wasLastLower = char.IsLower(text[i - 1]);

                if (i + 1 < text.Length) //is there a next
                {
                    var isNextUpper = char.IsUpper(text[i + 1]);

                    if (!isNextUpper) //if next is not upper (start of a word).
                    {
                        output.Append(splitChar);
                    }
                    else if (wasLastLower) //last was lower but i'm upper and my next is an upper (start of an achromin). 'abcdHTTP' 'abcd HTTP'
                    {
                        output.Append(splitChar);
                    }
                }
                else
                {
                    //last letter - if its upper and the last letter was lower 'abcd' to 'abcd A'
                    if (wasLastLower)
                    {
                        output.Append(splitChar);
                    }
                }
            }

            output.Append(c);
        }


        return output.ToString();

    }

Passes these tests, it doesn’t like numbers but i didn’t need it to.

    [TestMethod()]
    public void ToCamelCaseTest()
    {

        var testData = new string[] { "AAACamel", "AAA", "SplitThisByCamel", "AnA", "doesnothing", "a", "A", "aasdasdAAA" };
        var expectedData = new string[] { "AAA Camel", "AAA", "Split This By Camel", "An A", "doesnothing", "a", "A", "aasdasd AAA" };

        for (int i = 0; i < testData.Length; i++)
        {
            var actual = testData[i].SeperateByCamelCase();
            var expected = expectedData[i];
            Assert.AreEqual(actual, expected);
        }

    }

Questions:
Answers:

I also have an enum which I had to separate. In my case this method solved the problem-

string SeparateCamelCase(string str)
{
    for (int i = 1; i < str.Length; i++)
    {
        if (char.IsUpper(str[i]))
        {
            str = str.Insert(i, " ");
            i++;
        }
    }
    return str;
}