Useful WPF Data Converters

Just sharing the most common WPF data binding converters that I encounter on day to day basis. This should be beneficial for every WPF developer.

Usage

Usage in XAML should be as follows:

Define the XAML namespace to point to the common namespace where you would store your common converters. For example:
```
<Window ...
       xmlns:converters="clr-namespace:MyCompany.MyProject.MyConverters" >
```

Use converter like this:

<Button Content="Push Me" Click="ButtonConvertToBool_Click"
       Visibility="{Binding Path=Something, Converter={x:Static converters:BoolToVisibleConverter.Instance}}"
       IsEnabled="{Binding Path=SomeOtherThing, Converter={x:Static converters:IsNotNullConverter.Instance}}"
       />

Common Converters

IsNullConverter

Gets an object as an input and returns true if the object is not null; otherwise returns false.

public class IsNullConverter : IValueConverter
{
    private static readonly IsNullConverter _instance = new IsNullConverter();

    public static IsNullConverter Instance
    {
        get { return IsNullConverter._instance; }
    }

    private IsNullConverter()
    {
    }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        try
        {
            return (value == null);
        }
        catch
        {
            return null;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return Binding.DoNothing;
    }
}

IsNotNullConverter

Gets an object as an input and returns true if the object is null; otherwise returns false.

public class IsNotNullConverter : IValueConverter
{
    private static readonly IsNotNullConverter _instance = new IsNotNullConverter();

    public static IsNotNullConverter Instance
    {
        get { return IsNotNullConverter._instance; }
    }

    private IsNotNullConverter()
    {
    }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        try
        {
            return (value != null);
        }
        catch
        {
            return null;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return Binding.DoNothing;
    }
}

BoolToVisibleConverter

Gets a boolean as an input and returns Visibility.Visible if the boolean is true; otherwise returns Visibility.Collapsed.

public class BoolToVisibleConverter : IValueConverter
{
    private static readonly BoolToVisibleConverter _instance = new BoolToVisibleConverter();

    public static BoolToVisibleConverter Instance
    {
        get { return BoolToVisibleConverter._instance; }
    }

    object IValueConverter.Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        try
        {
            if ((bool)value)
                return Visibility.Visible;
            else
                return Visibility.Collapsed;
        }
        catch
        {
            return null;
        }
    }

    object IValueConverter.ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return Binding.DoNothing;
    }
}

BoolToVisibleExConverter

Gets a boolean as an input and returns Visibility.Visible if the boolean is true; otherwise returns Visibility.Hidden.

public class BoolToVisibleExConverter : IValueConverter
{
    private static readonly BoolToVisibleExConverter _instance = new BoolToVisibleExConverter();

    public static BoolToVisibleExConverter Instance
    {
        get { return BoolToVisibleExConverter._instance; }
    }

    private BoolToVisibleExConverter()
    {
    }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        try
        {
            if ((bool)value)
                return Visibility.Visible;
            else
                return Visibility.Hidden;
        }
        catch
        {
            return null;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return Binding.DoNothing;
    }
}

BoolToInvisibleConverter

Gets a boolean as an input and returns Visibility.Collapsed if the boolean is true; otherwise returns Visibility.Visible.

public class BoolToInvisibleConverter : IValueConverter
{
    private static readonly BoolToInvisibleConverter _instance = new BoolToInvisibleConverter();

    public static BoolToInvisibleConverter Instance
    {
        get { return BoolToInvisibleConverter._instance; }
    }

    object IValueConverter.Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value is bool)
        {
            if ((bool)value)
                return Visibility.Collapsed;
        }

        return Visibility.Visible;
    }

    object IValueConverter.ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return Binding.DoNothing;
    }
}

InvertBoolConverter

Gets a boolean as an input and returns true if the boolean is false; otherwise returns false.

public class InvertBoolConverter : IValueConverter
{
    private static readonly InvertBoolConverter _instance = new InvertBoolConverter();

    public static InvertBoolConverter Instance
    {
        get { return InvertBoolConverter._instance; }
    }

    private InvertBoolConverter()
    {
    }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        try
        {
            return !((bool)value);
        }
        catch
        {
            return null;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return Binding.DoNothing;
    }
}

EnumDescriptionConverter

Gets an enum object as an input and returns a string defined in the description attribute if defined; otherwise returns .ToString().

public class EnumDescriptionConverter : IValueConverter
{
    private static readonly EnumDescriptionConverter _instance = new EnumDescriptionConverter();

    public static EnumDescriptionConverter Instance
    {
        get { return EnumDescriptionConverter._instance; }
    }

    private EnumDescriptionConverter()
    {
    }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        try
        {
            FieldInfo fi = value.GetType().GetField(value.ToString());

            DescriptionAttribute[] attributes =
                (DescriptionAttribute[])fi.GetCustomAttributes(
                    typeof(DescriptionAttribute),
                    false);

            if (attributes != null &amp;&amp;
                attributes.Length &gt; 0)
                return attributes[0].Description;
            else
                return value.ToString();
        }
        catch
        {
            return null;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return Binding.DoNothing;
    }
}