windows - 如何在 WinRT 中将字符串颜色转换为画笔

Question

似乎 ConvertFromString 已从 WinRT 中消失。所以我很难找到一种在组合框中获取字符串并使用它设置文本前景和网格背景的方法。

这是我最近的尝试

private void ColorDropBox_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
    string backGroundColor = e.ToString();

    SolidColorBrush newcolor = new SolidColorBrush();

    newcolor = backGroundColor as SolidColorBrush;

    this.ContentRoot.Background = newcolor;
}

有什么建议/解决方法吗？

Answer 1

对于 WinRT

using Windows.UI;
using Windows.UI.Xaml.Media;


    public static Brush ColorToBrush(string color)
    {
        color = color.Replace("#", "");
        if (color.Length == 6)
        {
            return new SolidColorBrush(ColorHelper.FromArgb(255,
                byte.Parse(color.Substring(0, 2), System.Globalization.NumberStyles.HexNumber),
                byte.Parse(color.Substring(2, 2), System.Globalization.NumberStyles.HexNumber),
                byte.Parse(color.Substring(4, 2), System.Globalization.NumberStyles.HexNumber)));
        }
        else
        {
            return null;
        }
    }

Answer 2

库中没有提供转换。但是，转换例程很容易编写，例如http://blog.lookitskris.com/?p=22中提到的那个。

Answer 3

WinRT 中似乎缺少 ColorConverter，但稍加思考就可以轻松编写自己的。在下面的示例中，我创建了一些扩展方法，可以编写如下代码：

Color red = "Red".ConvertToColor(); or
Color color = colorName.ConvertToColor();

和

Background = colorName.CreateColorBrush();

为 WinRT 和 WPF 编译的扩展实现：

#if NETFX_CORE
using Windows.UI;
using Windows.UI.Xaml.Media;
#else
using System.Windows.Media;
#endif
using System;
using System.Globalization;
using System.Reflection;

namespace YourNiceExtensionsNamespace
{
    /// <summary>
    /// Extension to convert a string color name like "Red", "red" or "RED" into a Color.
    /// Using ColorsConverter instead of ColorConverter as class name to prevent conflicts with
    /// the WPF System.Windows.Media.ColorConverter.
    /// </summary>
    public static class ColorsConverter
    {
        /// <summary>
        /// Convert a string color name like "Red", "red" or "RED" into a Color.
        /// </summary>
        public static Color ConvertToColor(this string colorName)
        {
            if (string.IsNullOrEmpty(colorName)) throw new ArgumentNullException("colorName");
            MethodBase getColorMethod = FindGetColorMethod(colorName);
            if (getColorMethod == null)
            {
                // Using FormatException like the WPF System.Windows.Media.ColorConverter
                throw new FormatException(string.Format(CultureInfo.InvariantCulture, "Color name {0} not found in {1}",
                    colorName, typeof(Colors).FullName));
            }
            return (Color)getColorMethod.Invoke(null, null);
        }

        /// <summary>
        /// Create a SolidColorBrush from a color name
        /// </summary>
        public static Brush CreateColorBrush(this string colorName)
        {
            if (string.IsNullOrEmpty(colorName)) throw new ArgumentNullException("colorName");
            Color color = colorName.ConvertToColor();
            return new SolidColorBrush(color);
        }

        /// <summary>
        /// Verify if a string color name like "Red", "red" or "RED" is a known color in the static Colors class
        /// </summary>
        public static bool IsColorName(this string colorName)
        {
            if (string.IsNullOrEmpty(colorName)) throw new ArgumentNullException("colorName");
            return FindGetColorMethod(colorName) != null;
        }

        private static MethodBase FindGetColorMethod(string colorName)
        {
            foreach (PropertyInfo propertyInfo in typeof(Colors).GetTypeInfo().DeclaredProperties)
            {
                if (propertyInfo.Name.Equals(colorName, StringComparison.OrdinalIgnoreCase))
                {
                    MethodBase getMethod = propertyInfo.GetMethod;
                    if (getMethod.IsPublic && getMethod.IsStatic)
                        return getMethod;
                    break;
                }
            }
            return null;
        }
    }
}