Question

I have a property of type object, which contains an Enum value, and when I cast it using (int)value, it returns a string of the Enum’s name. Why?

The code where I noticed this is in this answer. Using Convert.ToInt32() correctly casts the Enum to an int, but I was just curious why I would get a string back when using (int). It doesn’t even throw me an error.

Edit

Here’s a quick sample. I commented where I put the breakpoint, and was using the immediate window to determine what the output was.

MainWindow.xaml.cs

public partial class MainWindow : Window
{
    public Int32 SomeNumber { get; set; }

    public MainWindow()
    {
        InitializeComponent();

        SomeNumber = 1;
        RootWindow.DataContext = this;

    }
}

public enum MyEnum
{
    Value1 = 1,
    Value2 = 2,
    Value3 = 3
}


/// <summary>
/// Returns true if the int value equals the Enum parameter, otherwise returns false
/// </summary>
public class IsIntEqualEnumParameterConverter : IValueConverter
{
    #region IValueConverter Members

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (parameter == null || value == null) return false;

        if (parameter.GetType().IsEnum && value is int)
        {
            // Breakpoint here
            return (int)parameter == (int)value;
        }
        return false;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }

    #endregion
}

MainWindow.xaml

<Window x:Class="WpfApplication5.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication5"
        Title="MainWindow" Height="350" Width="525"
        x:Name="RootWindow">

    <Window.Resources>
        <local:IsIntEqualEnumParameterConverter x:Key="IsIntEqualEnumParameterConverter" />
    </Window.Resources>

    <StackPanel>
        <TextBlock Text="{Binding SomeNumber, Converter={StaticResource IsIntEqualEnumParameterConverter}, ConverterParameter={x:Static local:MyEnum.Value1}}" />
    </StackPanel>
</Window>

Edit #2

Just hoping to clear up some confusion…

I said it was returning a string because running ?((int)parameter) in the Immediate Window was returning the enum name, while running ?System.Convert.ToInt32(parameter) was correctly displaying the int.

I found afterwards that it was actually evaluating correctly to the DataTrigger all along. I thought it wasn’t because my control wasn’t visible at runtime, however I discovered that was because of an error in my XAML (I forgot a Grid.Column property, so one control was overlapping another).

Sorry for the confusing question.

Edit #3

Here’s some console app code demonstrating the situation just for Jon 🙂

class Program
{
    static void Main(string[] args)
    {
        object value;
        value = Test.Value1;

        // Put breakpoint here
        // Run ?(int)value vs Convert.ToInt32(value) in the immediate window
        // Why does the first return Value1 while the 2nd returns 1?
        Console.ReadLine();
    }
}

public enum Test
{ 
    Value1 = 1
}

Answer 1

It sounds like you’re being duped by the Immediate Window. It’s not clear exactly what you did in the Immediate Window, but I can say with absolute certainty that if you cast to an int you do not get a string back. The type system completely prevents that from happening.