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Posted 3 Feb 2013
Licenced CPOL

WPF Enumeration Data Provider

, 11 Feb 2013
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WPF Enumeration Data Provider

In my recent adventures creating activity designers (Workflow Foundation 4+), I needed a way to bind a ComboBox with an enumeration and didn't want to manually wire up events in the code behind. Fortunately, I found some examples on how to use an ObjectDataProvider. This worked great, but I realized the setup was more than I wanted to do every time I needed an enumerated bound ComoBox and came up with my own EnumerationDataProvider. In addition to simplifying the setup, I added the following features / customizations...

  • Inherits from ObjectDataProvider and sets up the properties and parameters for you.
  • Automatically associate the None enumeration value to a blank value.
  • Allows you to override the None value and None display value.
  • Sorts the enumerations values by name.

For those who are not aware, custom activity designers are created essentially using WPF.
Here is the implementation...

public class EnumerationDataProvider : ObjectDataProvider
    public Type EnumerationType { get; set; }

    public string NoneValue { get; set; }

    public string NoneDisplayValue { get; set; }

    public EnumerationDataProvider()
        this.MethodName = "GetEnumerations";
        this.ObjectType = typeof(EnumerationHelper);

    protected override void EndInit()


    private static class EnumerationHelper
        private const string NoneDefaultValue = "None";
        private const string NoneDisplayDefaultValue = "";

        public static IDictionary<object, string> GetEnumerations(
            Type enumType, string noneValue, string noneDisplayValue)
            // Setup defaults if none exists.
            if (string.IsNullOrWhiteSpace(noneValue)) noneValue = NoneDefaultValue;
            if (string.IsNullOrWhiteSpace(noneDisplayValue)) noneDisplayValue = NoneDisplayDefaultValue;

            IDictionary<object, string> items = new Dictionary<object, string>();

            // Find the None enumeration value.
            string noneStringValue = (from n in Enum.GetNames(enumType) 
                                        where string.Compare(n, noneValue, 
                                              StringComparison.OrdinalIgnoreCase) == 0 
                                        select n).FirstOrDefault();

            bool hasNoneValue = !string.IsNullOrWhiteSpace(noneStringValue);

            object noneEnumerationValue = null;
            if (hasNoneValue)
                // Parse the None value if it exists and add it as the first item.
                noneEnumerationValue = Enum.Parse(enumType, noneStringValue, true);
                items.Add(noneEnumerationValue, noneDisplayValue);

            // Select all enumeration values where not equal to the None value and order by 
            // the enumeration value name.
            var orderedEnums = from v in Enum.GetValues(enumType).Cast<object>() 
                                where !v.Equals(noneEnumerationValue) 
                                orderby Convert.ToString(v) select v;

            foreach (var value in orderedEnums)
                items.Add(value, Convert.ToString(value));

            return items;


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Stephen Brannan
Software Developer (Senior)
United States United States
No Biography provided

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Comments and Discussions

QuestionUsage sample Pin
Reinhard Ostermeier11-Feb-13 22:01
memberReinhard Ostermeier11-Feb-13 22:01 
AnswerRe: Usage sample Pin
Stephen Brannan12-Feb-13 8:29
memberStephen Brannan12-Feb-13 8:29 
GeneralRe: Usage sample Pin
Reinhard Ostermeier12-Feb-13 23:03
memberReinhard Ostermeier12-Feb-13 23:03 
GeneralRe: Usage sample Pin
Stephen Brannan13-Feb-13 13:28
memberStephen Brannan13-Feb-13 13:28 

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