c# - Custom define enum names for combobox

Question

I have a namespace in which I have declared an enum as follows:

namespace IXMSoft.Business.SDK.Data
{
using System;

public enum BaudRate
{
    BR115200 = 7,
    BR19200 = 4,
    BR230400 = 8,
    BR2400 = 1,
    BR38400 = 5,
    BR4800 = 2,
    BR57600 = 6,
    BR9600 = 3
  }
}

When I retrieve these values in a combo box, which is in another namespace, using the statement

comboBox1.Items.Add(BaudRate.BR5700);

it shows the value as for example

"BR5700"

I want to remove BR in front and just want to display the value as "5700". What should I do?

Answer 1

use the DescriptionAttribute and an appropriate extension method to read it out.

public enum BaudRate
{
    [Description("115200 kb")]
    BR115200 = 7,
    [Description("19200 kb")]
    BR19200 = 4,
    [Description("230400 kb")]
    BR230400 = 8,
    [Description("2400 kb")]
    BR2400 = 1,
    [Description("115200 kb")]
    BR38400 = 5,
    [Description("4800 kb")]
    BR4800 = 2,
    [Description("57600 kb")]
    BR57600 = 6,
    [Description("9600 kb")]
    BR9600 = 3
}

The extension method:

public static class EnumExtension
{
    /// <summary>
    /// Gets the string of an DescriptionAttribute of an Enum.
    /// </summary>
    /// <param name="value">The Enum value for which the description is needed.</param>
    /// <returns>If a DescriptionAttribute is set it return the content of it.
    /// Otherwise just the raw name as string.</returns>
    public static string Description(this Enum value)
    {
        if (value == null)
        {
            throw new ArgumentNullException("value");
        }

        string description = value.ToString();
        FieldInfo fieldInfo = value.GetType().GetField(description);
        DescriptionAttribute[] attributes =
           (DescriptionAttribute[])
         fieldInfo.GetCustomAttributes(typeof(DescriptionAttribute), false);

        if (attributes != null && attributes.Length > 0)
        {
            description = attributes[0].Description;
        }

        return description;
    }

    /// <summary>
    /// Creates an List with all keys and values of a given Enum class
    /// </summary>
    /// <typeparam name="T">Must be derived from class Enum!</typeparam>
    /// <returns>A list of KeyValuePair&lt;Enum, string&gt; with all available
    /// names and values of the given Enum.</returns>
    public static IList<KeyValuePair<Enum, string>> ToList<T>() where T : struct
    {
        var type = typeof(T);

        if (!type.IsEnum)
        {
            throw new ArgumentException("T must be an enum");
        }

        return (IList<KeyValuePair<Enum, string>>)
                Enum.GetValues(type)
                    .OfType<Enum>()
                    .Select(e => new KeyValuePair<Enum, string>(e, e.Description()))
                    .ToArray();
    }

    public static T GetValueFromDescription<T>(string description) where T : struct
    {
        var type = typeof(T);

        if(!type.IsEnum)
        {
            throw new ArgumentException("T must be an enum");
        }

        foreach(var field in type.GetFields())
        {
            var attribute = Attribute.GetCustomAttribute(field,
                typeof(DescriptionAttribute)) as DescriptionAttribute;

            if(attribute != null)
            {
                if(attribute.Description == description)
                {
                    return (T)field.GetValue(null);
                }
            }
            else
            {
                if(field.Name == description)
                {
                    return (T)field.GetValue(null);
                }
            }
        }

        throw new ArgumentOutOfRangeException("description");
        // or return default(T);
    }
}

At the and you can simply apply this to your combo box by calling:

var list = EnumExtension.ToList<BaudRate>();
myComboBox.DataSource = list;
myComboBox.ValueMember = "Key";
myComboBox.DisplayMember = "Value";