How to display an enum in WinForms ComboBox or ASP.NET Core Select

This article demonstrates how to display enum members using English text rather than each enum member name and there is a comparison to how it's done with ASP.NET Core which is a good deal easier than in Windows Forms.

ASP.NET Core

With ASP.NET Core to display enum members in a dropdown we can use Html.GetEnumSelectList<YourEnum>()

With that in the example below the enum used where Description attruibute is used to properly display the text rather than the enum members.

public enum CustomerType
{
    [Display(Name = "Private")]
    PrivateSector,
    [Display(Name = "Public")]
    PublicSector
}

HTML code

<select asp-for="Type" class="form-control"  asp-items="Html.GetEnumSelectList<CustomerType>()">
    <option>Select type ...</option>
</select>

Which gives us the following

Side notes

Alternated default validation from standard in the box.

Has a custom validator for CustomerType to ensure Select is not used for a post.

public class RequiredTypeAttribute : RequiredAttribute
{
    public override bool IsValid(object? value)
    {
        if (value is null) return false;

        if (value is CustomerType selection)
        {
            return selection != CustomerType.Select;
        }
        return false;
    }
}

Windows forms

We will use the same model as in the ASP.NET Core sample but remove the Display attruibute with a Description attruibute.

public enum CustomerType
{
    [Description("Select type...")]
    Select,
    [Description("Private")]
    PrivateSector,
    [Description("Public")]
    PublicSector
}

The following method is used to obtain each enum member value and text description

public class EnumHelper
{
    public static List<KeyValuePair<string, Enum>> GetItemsAsDictionary<T>() =>
        Enum.GetValues(typeof(T)).Cast<T>()
            .Cast<Enum>()
            .Select(value => new KeyValuePair<string, Enum>(
                (Attribute.GetCustomAttribute(value.GetType().GetField(value.ToString())!,
                    typeof(DescriptionAttribute)) as DescriptionAttribute)!.Description, value))
            .ToList();

}

Then in form shown event, with a ComboBox named TypeComboBox setup DisplayMember to the Key, the text description of the enum than set ValueMember to the actual enum. Now we can set the ComoBox.DataSource.

TypeComboBox.DisplayMember = "Key";
TypeComboBox.ValueMember = "Value";
TypeComboBox.DataSource = GetItemsAsDictionary<CustomerType>(); ;

To get the selection, in a button click event.

Enum.TryParse(TypeComboBox.SelectedValue.ToString(), out CustomerType customerType);

MessageBox.Show(customerType == CustomerType.Select 
    ? "Please make a selection" : $"Selected {customerType}");

Downside to this solution is a member for CustomerType is needed for prompting for a selection.