c# - Is it possible to create a generic Int-to-Enum Converter?

Question

I'd like to be able to say

<DataTrigger Binding="{Binding SomeIntValue}" 
             Value="{x:Static local:MyEnum.SomeValue}">

and to have it resolve as True if the int value is equal to (int)MyEnum.Value

I know I could make a Converter that returns (MyEnum)intValue, however then I'd have to make a converter for every Enum type I use in my DataTriggers.

Is there a generic way to create a converter that would give me this kind of functionality?

Answer 1

It is possible to create a converter between enum values and their underlying integral types in a reusable way -- that is, you don't need to define a new converter for each enum types. There's enough information provided to Convert and ConvertBack for this.

public sealed class BidirectionalEnumAndNumberConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null)
            return null;

        if (targetType.IsEnum)
        {
            // convert int to enum
            return Enum.ToObject(targetType, value);
        }

        if (value.GetType().IsEnum)
        {
            // convert enum to int
            return System.Convert.ChangeType(
                value,
                Enum.GetUnderlyingType(value.GetType()));
        }

        return null;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        // perform the same conversion in both directions
        return Convert(value, targetType, parameter, culture);
    }
}

When invoked, this converter flips the value's type between int/enum value based purely on the value and targetType values. There are no hard-coded enum types.