Skip to main content

Binding Enum with DescriptionAttribute in WPF

Binding an enumeration to a ComboBox can be done in several ways. In most cases you don't want to display the value itself, but a more user friendly description. One common approach is to use the DescriptionAttribute on the Enum values to supply a description for each value. This is all possible in a very MVVM friendly way.

First step is to add the DescriptionAttribute to the values of the enumeration.

public enum MyValues
{
    [Description("First value")]
    First,

    [Description("Second value")]
    Second
}

To retrieve the description from the enum we use a simple extension method. This method returns the value of the DescriptionAttribute if it exists, otherwise the string representation of the enum value is returned.

public static string GetDescription(this Enum value)
{
    var fieldInfo = value.GetType().GetField(value.ToString());
    var attribute = fieldInfo.GetCustomAttributes(typeof(DescriptionAttribute), false).FirstOrDefault() as DescriptionAttribute;

    return attribute != null ? attribute.Description : value.ToString();
}

With this extension method it is really easy to write a generic enum description converter to use where ever an enum value is presented to the user. But the more interesting case is where we want to present the enumeration in a ComboBox or a similar control. To accomplish this you can use a MarkupExtension. (Please note that this code is stripped from all type validation and such to be easier to read.)

public class EnumExtension : MarkupExtension
{
    private readonly Type _enumType;

    public EnumExtension(Type enumType)
    {
        _enumType = enumType;
    }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return (from object enumValue in Enum.GetValues(_enumType)
                select new EnumMember {Value = enumValue, Description = ((Enum)enumValue).GetDescription()}).ToArray();
    }

    public class EnumMember
    {
        public string Description { get; set; }
        public object Value { get; set; }
    }
}

The DescriptionAttribute together with these extensions gives us a really neat way of populating the values of an enum into a ComboBox.

<ComboBox SelectedValue="{Binding MyValue}"
          ItemsSource="{Binding Source={my:EnumExtension {x:Type MyValues}}}"
          DisplayMemberPath="Description" SelectedValuePath="Value" />

Comments

  1. 1xbet 1xbet 10cric 10cric 카지노 카지노 온라인카지노 온라인카지노 1xbet 1xbet fun88 fun88 687

    ReplyDelete
  2. Tania's Pro Titanium Hockey VR - The Tania's Pro - Titanium
    Tania's Pro is titanium rod in leg an upcoming titanium hoop earrings video game developed by titanium tent stakes Tania titanium chain for HTC Vive, the HTC Vive, PC, micro touch titanium trimmer Vive, PlayStation VR and PlayStation VR.

    ReplyDelete

Post a Comment

Popular posts from this blog

Programming AD with C#.NET – part 4

Our transition to the  System.DirectoryServices.Protocols  has in the whole gone very smooth, but there have been some issues with one environment that contains subdomains. Most things are working fine, but writing to a subdomain does not work in the same way as it did before. What is generally bad with the  System.DirectoryServices.Protocols is the documentation, which is practically non-existent. But most things can  be figured out anyway since most classes just are wrappers for the wldap32.dll, which in turn is way better documented. I would like to have as little bindings to a specific server as possible but still be able to access the domain. In the  LdapConnection  it is possible to set the identifier to null and use the executing computer as a starting point to find a domain controller. But sometimes I must know that I am using a Global Catalog, and with more and more RODC in the environment I sometimes must know that I am working against a writeable domain controller.

jQuery file upload with Bootstrap progress bar

Performing an asynchronous file upload from the browser is a common problem with almost as many solutions as there are developers. The following solution is the best fit for my needs, and also works well with most popular browsers. Backwards compatibility is not an issue in this case which is great, because I can use the new technologies as they are supposed to be used. Everything is put together in JSFiddle for a working example . I will continue to explain the parts below... First, the input field needs to be styled as a button. The form tag is only present for us to be able to reset the file input field later on. <form>     <span class="fileUpload btn btn-default">         <span class="glyphicon glyphicon-upload"></span> Upload file         <input type="file" id="uploadFile" />     </span> </form> .fileUpload { position: relative; overflow: hidden; } .fileUpload input { position: a

Google+ finally for everyone!

There have been a lot of whining on Google from their Apps-users since the launch of  Google+  for everyone with a regular Google-account. The Apps-users have not been able to use  Google+ , until now! (actually  october 27 ) As usual I am impressed with most of the things Google accomplishes, but now when all of their services have gotten a visual and functional touchup I am getting really impressed. As someone at an early stage pointed out it is really sweet of Google to play naive and let me fill in my profile information when I create my profile (as if Google did not already know), but after a few clicks I am on the go. My albums from Picasa is automatically integrated and even the pictures I have uploaded to this blog is shown in  Google+ . But what happens next? Practically no one of my friends are on  Google+  so what do I use it for? I guess we will see. Hopefully there will be even more integration between the social networks in the future. I am anyhow very satified with