我希望通过将标签的背景颜色绑定到三个滑动条来创建颜色选择工具，每个滑动条代表红色，蓝色或绿色。
现在我知道如何将背景颜色绑定到单个字符串，但是如何绑定到三个不同的控件呢？
答案 0 :(得分：4)
您需要创建IMultiValueConverter课程，并使用MultiBinding。如果您要绑定Control的{{1}}媒体资源，则需要返回Background。一个天真的实现看起来像这样：
Brush然后你会像这样使用它：
public class BrushConverter : IMultiValueConverter
{
public object Converter(object[] values, Type targetType, object parameter, CultureInfo culture)
{
return new SolidColorBrush(
Color.FromArgb(255, Convert.ToByte(values[0]),
Convert.ToByte(values[1]), Convert.ToByte(values[2])));
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
// this can be implemented fairly easily
throw new NotSupportedException();
}
}
答案 1 :(得分：0)
您应该使用MultiBinding。您需要编写将三个整数（红色，绿色和蓝色）转换为Color的转换器。
答案 2 :(得分：0)
我最近使用附加属性解决了这个问题
下载完整的代码
public static class BrushExtender
{
public readonly static DependencyProperty BrushProperty =
DependencyProperty.RegisterAttached("Brush", typeof(Brush),
typeof(BrushExtender), new PropertyMetadata(Brushes.Black, DoBrushChanged));
public readonly static DependencyProperty RedChannelProperty =
DependencyProperty.RegisterAttached("RedChannel", typeof(int),
typeof(BrushExtender), new PropertyMetadata(DoColorChangedRed));
public readonly static DependencyProperty GreenChannelProperty =
DependencyProperty.RegisterAttached("GreenChannel", typeof(int),
typeof(BrushExtender), new PropertyMetadata(DoColorChangedGreen));
public readonly static DependencyProperty BlueChannelProperty =
DependencyProperty.RegisterAttached("BlueChannel", typeof(int),
typeof(BrushExtender), new PropertyMetadata(DoColorChangedBlue));
public readonly static DependencyProperty AlphaChannelProperty =
DependencyProperty.RegisterAttached("AlphaChannel", typeof(int),
typeof(BrushExtender), new PropertyMetadata(DoColorChangedAlpha));
public readonly static DependencyProperty ColourValueProperty =
DependencyProperty.RegisterAttached("ColourValue", typeof(string),
typeof(BrushExtender), new PropertyMetadata(DoValueChanged));
public static void SetRedChannel(DependencyObject o, int value)
{
o.SetValue(RedChannelProperty, value);
}
public static void SetGreenChannel(DependencyObject o, int value)
{
o.SetValue(GreenChannelProperty, value);
}
public static void SetBlueChannel(DependencyObject o, int value)
{
o.SetValue(BlueChannelProperty, value);
}
public static void SetAlphaChannel(DependencyObject o, int value)
{
o.SetValue(AlphaChannelProperty, value);
}
public static void SetBrush(DependencyObject o, SolidColorBrush brush)
{
o.SetValue(BrushProperty, brush);
}
public static void SetColourValue(DependencyObject o, string value)
{
o.SetValue(ColourValueProperty, value);
}
private static void DoColorChangedRed(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var color = ((SolidColorBrush)d.GetValue(BrushProperty)).Color;
DoColorChange(d, (int)e.NewValue, c => c.R, () =>
Color.FromArgb(color.A, ((byte)(int)e.NewValue), color.G, color.B));
}
private static void DoColorChangedGreen(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var color = ((SolidColorBrush)d.GetValue(BrushProperty)).Color;
DoColorChange(d, (int)e.NewValue, c => c.G, () =>
Color.FromArgb(color.A, color.R, ((byte)(int)e.NewValue), color.B));
}
private static void DoColorChangedBlue(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var color = ((SolidColorBrush)d.GetValue(BrushProperty)).Color;
DoColorChange(d, (int)e.NewValue, c => c.B, () =>
Color.FromArgb(color.A, color.R, color.G, (byte)(int)e.NewValue));
}
private static void DoColorChangedAlpha(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var color = ((SolidColorBrush)d.GetValue(BrushProperty)).Color;
DoColorChange(d, (int)e.NewValue, c => c.A, () =>
Color.FromArgb((byte)(int)e.NewValue, color.R, color.G, color.B));
}
private static void DoColorChange(DependencyObject d, int newValue, Func<Color, int> colorCompare,
Func<Color> getColor)
{
var color = ((SolidColorBrush)d.GetValue(BrushProperty)).Color;
if (colorCompare(color) == newValue)
return;
var newBrush = new SolidColorBrush(getColor());
d.SetValue(BrushProperty, newBrush);
d.SetValue(ColourValueProperty, newBrush.Color.ToString());
}
private static void DoValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var color = ((SolidColorBrush)d.GetValue(BrushProperty)).Color;
if (color.ToString() == (string)e.NewValue)
return;
Color? newColour = null;
try
{
newColour = (Color) ColorConverter.ConvertFromString((string)e.NewValue);
}
catch { }
if (newColour == null)
return;
var newBrush = new SolidColorBrush(newColour.Value);
d.SetValue(BrushProperty, newBrush);
}
private static void DoBrushChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue == e.OldValue)
return;
var colour = ((SolidColorBrush)e.NewValue).Color;
d.SetValue(RedChannelProperty, (int)colour.R);
d.SetValue(GreenChannelProperty, (int)colour.G);
d.SetValue(BlueChannelProperty, (int)colour.B);
d.SetValue(AlphaChannelProperty, (int)colour.A);
d.SetValue(ColourValueProperty, colour.ToString());
}
}
并且继承了XAML
<Window x:Class="ColourBlender.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ColourBlender="clr-namespace:ColourBlender"
Title="MainWindow" Height="350" Width="525">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<TextBlock Text="Red" />
<TextBlock Text="Green" Grid.Row="1" />
<TextBlock Text="Blue" Grid.Row="2" />
<TextBlock Text="Alpha" Grid.Row="3" />
<Slider Name="redSlider" Grid.Column="1" Minimum="0" Maximum="255" Width="200" Height="20"
Grid.ColumnSpan="2" Value="{Binding ElementName=rect,
Path=(ColourBlender:BrushExtender.RedChannel), Mode=TwoWay}" />
<Slider Name="greenSlider" Grid.Column="1" Grid.Row="1" Minimum="0" Maximum="255" Width="200" Height="20"
Grid.ColumnSpan="2" Value="{Binding ElementName=rect,
Path=(ColourBlender:BrushExtender.GreenChannel), Mode=TwoWay}" />
<Slider Name="blueSlider" Grid.Column="1" Grid.Row="2" Minimum="0" Maximum="255" Width="200" Height="20"
Grid.ColumnSpan="2" Value="{Binding ElementName=rect,
Path=(ColourBlender:BrushExtender.BlueChannel), Mode=TwoWay}" />
<Slider Name="alphaSlider" Grid.Column="1" Grid.Row="3" Minimum="0" Maximum="255" Width="200" Height="20"
Grid.ColumnSpan="2" Value="{Binding ElementName=rect,
Path=(ColourBlender:BrushExtender.AlphaChannel), Mode=TwoWay}" />
<Rectangle Fill="SandyBrown" Name="rect" Width="200" Height="50" Grid.Row="4" Grid.ColumnSpan="3"
Margin="0,20,0,10" ColourBlender:BrushExtender.Brush="{Binding RelativeSource={RelativeSource Self},
Path=Fill, Mode=TwoWay}"/>
<TextBlock Text="Colour Value" Margin="5,0,5,0" Grid.Row="5" HorizontalAlignment="Center" />
<TextBox Text="{Binding ElementName=rect, Path=(ColourBlender:BrushExtender.ColourValue), Mode=TwoWay}"
Margin="0,0,0,0" Grid.Row="5" Grid.Column="1" Width="100" HorizontalAlignment="Center" />
<Button Content="Update" Grid.Row="5" Grid.Column="3" />
</Grid>