注：
需要继承IMultiValueConverter接口，接口使用和IValueConverter逻辑相同。
一、MultiBinding+Converter 多值绑定及多值转换实例
当纵向流量大于横向流量时指示灯应为绿色，当纵向流量小于横向流量时指示灯应为红色，否则指示灯为黄色。
1、定制ColorConverter类，此时Convert中参数是object[] values，values[0]对应MultiBinding中的第一个Binding值，这里是纵向流量值，依此类推，可以在MultiBinding对象中指定多个绑定。
public class ColorConverter : IMultiValueConverter
{
//正向修改
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
if (values == null || values.Length < )
return DependencyProperty.UnsetValue;
double verValue = (double)values[];
double horValue = (double)values[];
if (verValue > horValue)
return new SolidColorBrush(Colors.Green);
else if (verValue < horValue)
return new SolidColorBrush(Colors.Red);
return new SolidColorBrush(Colors.Yellow);
}
//反向修改
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
//返回空，标记不可双向转换
return null;
}
}
2.Xaml定义
添加命名空间
xmlns:local="clr-namespace:AudioDemo.View"
<Window.Resources>
<local:ColorConverter x:Key="cvtColor"/>
</Window.Resources>
<Grid>
<Label x:Name="label" Content="纵向值：" HorizontalAlignment="Left" Margin="10,40,0,0" VerticalAlignment="Top"/>
<Label x:Name="label1" Content="横向值：" HorizontalAlignment="Left" Margin="10,80,0,0" VerticalAlignment="Top"/>
<Slider x:Name="sliderVer" HorizontalAlignment="Left" Margin="75,43,0,0" VerticalAlignment="Top" Width="192"/>
<Slider x:Name="sliderHor" HorizontalAlignment="Left" Margin="75,81,0,0" VerticalAlignment="Top" Width="192"/>
<Ellipse HorizontalAlignment="Left" Height="100" Margin="75,120,0,0" Stroke="Black" VerticalAlignment="Top" Width="100">
<Ellipse.Fill>
<MultiBinding Converter="{StaticResource cvtColor}">
<Binding Path="Value" ElementName="sliderVer"/>
<Binding Path="Value" ElementName="sliderHor"/>
</MultiBinding>
</Ellipse.Fill>
</Ellipse>
</Grid>
二、RGB颜色混合实例
1.转换器定义
public class RGBConverter : IMultiValueConverter
{
//正向修改，整合颜色值
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
if (values == null || values.Length < )
return null;
byte r = System.Convert.ToByte(values[]);
byte g = System.Convert.ToByte(values[]);
byte b = System.Convert.ToByte(values[]);
Color col = Color.FromRgb(r, g, b);
SolidColorBrush brush = new SolidColorBrush(col);
return brush;
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
return null;
}
}
2.Xaml定义
别忘先添加命名空间
xmlns:local="clr-namespace:AudioDemo.View"
<Window.Resources>
<local:RGBConverter x:Key="rgbCvt"/>
</Window.Resources>
<Grid>
<Label x:Name="label" Content="Red:" HorizontalAlignment="Left" Margin="10,48,0,0" VerticalAlignment="Top"/>
<Label x:Name="label_Copy" Content="Green:" HorizontalAlignment="Left" Margin="7,85,0,0" VerticalAlignment="Top"/>
<Label x:Name="label_Copy1" Content="Blue:" HorizontalAlignment="Left" Margin="7,123,0,0" VerticalAlignment="Top"/>
<Slider x:Name="slider_r" Minimum="0" Maximum="255" Ticks="1" HorizontalAlignment="Left" Margin="68,53,0,0" VerticalAlignment="Top" Width="207"/>
<Slider x:Name="slider_g" Minimum="0" Maximum="255" Ticks="1" HorizontalAlignment="Left" Margin="68,91,0,0" VerticalAlignment="Top" Width="207"/>
<Slider x:Name="slider_b" Minimum="0" Maximum="255" Ticks="1" HorizontalAlignment="Left" Margin="68,124,0,0" VerticalAlignment="Top" Width="207"/>
<Rectangle HorizontalAlignment="Left" Height="90" Margin="68,160,0,0" Stroke="Black" VerticalAlignment="Top" Width="142">
<Rectangle.Fill>
<MultiBinding Converter="{StaticResource rgbCvt}">
<Binding ElementName="slider_r" Path="Value"></Binding>
<Binding ElementName="slider_g" Path="Value"></Binding>
<Binding ElementName="slider_b" Path="Value"></Binding>
</MultiBinding>
</Rectangle.Fill>
</Rectangle> </Grid>
运行结果：