use of boolean to color converter in XAML

Question

I am working on WPF application.I have bound my textblock to my button. I want to set foreground of my textblock to black color when its associated button\'s isEnabled is tr

Answer 1

To make this converter general you may use a ConverterParameter for specifying the colors which is to be inserted when value is true or false. Also the opacity may be of interest. I here provide the Converter I taking the parameter [ColorNameIfTrue;ColorNameIfFalse;OpacityNumber].

Since the SolidColorBrush() method mentioned by @user1101511 is part of the System.Windows.Media library, it uses the Color type from that same library. This type does not have a Color.FromName() method, like the System.Drawing.Color class.

Therfore I made a helper method called ColorFromName(string name). I specify "LimeGreen" as a fallback color if the interpertation of ConverterParameter fails. In my case I want the output to be "Transparent" when value is false.

using System;
using System.Globalization;
using System.Windows.Data;
using System.Windows.Media;

namespace MyConverters
{
    [ValueConversion(typeof(bool), typeof(SolidColorBrush))]
    class BoolToColorBrushConverter : IValueConverter
    {
        #region Implementation of IValueConverter

        /// 

        /// 
        /// 
        /// Bolean value controlling wether to apply color change
        /// 
        /// A CSV string on the format [ColorNameIfTrue;ColorNameIfFalse;OpacityNumber] may be provided for customization, default is [LimeGreen;Transperent;1.0].
        /// 
        /// A SolidColorBrush in the supplied or default colors depending on the state of value.
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        SolidColorBrush color;
        // Setting default values
        var colorIfTrue = Colors.LimeGreen;
        var colorIfFalse = Colors.Transparent;
        double opacity = 1;
        // Parsing converter parameter
        if (parameter != null)
        {
            // Parameter format: [ColorNameIfTrue;ColorNameIfFalse;OpacityNumber]
            var parameterstring = parameter.ToString();
            if (!string.IsNullOrEmpty(parameterstring))
            {
                var parameters = parameterstring.Split(';');
                var count = parameters.Length;
                if (count > 0 && !string.IsNullOrEmpty(parameters[0]))
                {
                    colorIfTrue = ColorFromName(parameters[0]);
                }
                if (count > 1 && !string.IsNullOrEmpty(parameters[1]))
                {
                    colorIfFalse = ColorFromName(parameters[1]);
                }
                if (count > 2 && !string.IsNullOrEmpty(parameters[2]))
                {
                    double dblTemp;
                    if (double.TryParse(parameters[2], NumberStyles.AllowDecimalPoint, CultureInfo.InvariantCulture.NumberFormat, out dblTemp))
                        opacity = dblTemp;
                }
            }
        }
        // Creating Color Brush
        if ((bool) value)
        {
            color = new SolidColorBrush(colorIfTrue);
            color.Opacity = opacity;
        }
        else
        {
            color = new SolidColorBrush(colorIfFalse);
            color.Opacity = opacity;
        }
        return color;
    }


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

    #endregion

    public static Color ColorFromName(string colorName)
    {
        System.Drawing.Color systemColor = System.Drawing.Color.FromName(colorName);
        return Color.FromArgb(systemColor.A, systemColor.R, systemColor.G, systemColor.B);
    }
}

From xaml the above converter may be used like this:

Background="{Binding MyBooleanValue, Converter={StaticResource BoolToColorBrushConverter}, ConverterParameter=LimeGreen;Transperent;0.2, Mode=OneWay}"