问题
I'm trying to create a custom user control that will allow a user to define a color in WPF. I've done this before in WinForms but in WPF it seems to be not as straight forward. This is also my first time dealing with a multi-converter.
The control has 3 Sliders - like so :
<Slider x:Name="sdrRed" Height="32" LargeChange="5" SmallChange="1" Maximum="255" Width="321" TickPlacement="Both"/>
The only difference is the name for each - sdrRed, sdrGreen, and sdrBlue.
This is the multi-value converter :
public class ByteToColorConverter : IMultiValueConverter
{
public object Convert( object[ ] values, Type targetType, object parameter, System.Globalization.CultureInfo culture ) {
return Color.FromArgb( (byte)values[0], (byte)values[1], (byte)values[2], (byte)values[3]);
}
public object[ ] ConvertBack( object value, Type[ ] targetTypes, object parameter, System.Globalization.CultureInfo culture ) {
Color C = ( Color )value;
return new object[ ] { C.A, C.R, C.G, C.B };
}
}
This is as far as I have been able to get - I haven't been able to find an example of how to proceed.
Also - how can I pass values to the multiconverter that are static, so that I may define a color with only a single slider (say, so that I may define shades of Red, Blue or Green)?
EDIT
For some clarity; The control itself will have a dependency property :
private static readonly DependencyProperty
_Color = DependencyProperty.Register( "Color", typeof( Color ), typeof( ColorDefiner ), new PropertyMetadata( Colors.Black ) );
public Color Color {
get { return ( Color )this.GetValue( ColorDefiner._Color ); }
set { this.SetValue( ColorDefiner._Color, value ); }
}
This control will pass the converted Color value to that binding, so that other colors may be bound to it. I hope that clears things up.
回答1:
First of all, I'd recommend making these changes to your ByteToColorConverter:
public class DoubleToColorConverter : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
// Values bound to sliders are going to be doubles.
return Color.FromScRgb((float)(double)values[0], (float)(double)values[1], (float)(double)values[2], (float)(double)values[3]);
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
{
Color C = (Color)value;
return new object[] { (double)C.ScA, (double)C.ScR, (double)C.ScG, (double)C.ScB };
}
}
I've switched from bytes to doubles, as the slider value you're trying to bind to will only return/accept doubles. The (float)(double) cast is to deal with unboxing the values in the array.
With this XAML, I was able to get a basic ARGB colour mixer working. Notice I've changed the Min/Max values on the slider, now we're not dealing with bytes anymore.
<StackPanel>
<Slider x:Name="sdrAlpha" Height="32" LargeChange="0.5" SmallChange="0.1" Minimum="0" Maximum="1" Width="321" TickPlacement="Both"/>
<Slider x:Name="sdrRed" Height="32" LargeChange="0.5" SmallChange="0.1" Minimum="0" Maximum="1" Width="321" TickPlacement="Both"/>
<Slider x:Name="sdrGreen" Height="32" LargeChange="0.5" SmallChange="0.1" Minimum="0" Maximum="1" Width="321" TickPlacement="Both"/>
<Slider x:Name="sdrBlue" Height="32" LargeChange="0.5" SmallChange="0.1" Minimum="0" Maximum="1" Width="321" TickPlacement="Both"/>
<Border x:Name="colourBorder" Height="200" HorizontalAlignment="Stretch">
<Border.Background>
<SolidColorBrush>
<SolidColorBrush.Color>
<MultiBinding Converter="{StaticResource colorConverter}">
<Binding ElementName="sdrAlpha" Path="Value" Mode="TwoWay" />
<Binding ElementName="sdrRed" Path="Value" Mode="TwoWay" />
<Binding ElementName="sdrGreen" Path="Value" Mode="TwoWay" />
<Binding ElementName="sdrBlue" Path="Value" Mode="TwoWay" />
</MultiBinding>
</SolidColorBrush.Color>
</SolidColorBrush>
</Border.Background>
</Border>
</StackPanel>
If you wanted to bind a single slider to the converter, you could update your converter to inspect the number of values in the values[] array. You could perhaps use the ConverterParameter to pass in the colour you'd like that single slider to affect ... something like this:
<MultiBinding Converter="{StaticResource colorConverter}" ConverterParameter="Red">
<Binding ElementName="sdrRed" Path="Value" Mode="TwoWay" />
</MultiBinding>
回答2:
Okay - I want to thank everyone for their help; I was finally able to come up with a solution - in the event anyone is interested or stumbles upon this, it's also a good lesson in MVVM (maybe; I don't know...).
Anyway :
This is the MVVM I implemented :
public class ColorViewModel : INotifyPropertyChanged {
public event PropertyChangedEventHandler PropertyChanged;
private Color _Color = Colors.Black;
public double A {
get { return this.Color.ScA; }
set {
this._Color.ScA = ( float )value;
if ( this.PropertyChanged != null ) {
this.PropertyChanged( this, new PropertyChangedEventArgs( "A" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Color" ) );
}
}
}
public double R {
get { return this.Color.ScR; }
set {
this._Color.ScR = ( float )value;
if ( this.PropertyChanged != null ) {
this.PropertyChanged( this, new PropertyChangedEventArgs( "R" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Red" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Color" ) );
}
}
}
public double G {
get { return this.Color.ScG; }
set {
this._Color.ScG = ( float )value;
if ( this.PropertyChanged != null ) {
this.PropertyChanged( this, new PropertyChangedEventArgs( "G" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Green" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Color" ) );
}
}
}
public double B {
get { return this._Color.ScB; }
set {
this._Color.ScB = ( float )value;
if ( this.PropertyChanged != null ) {
this.PropertyChanged( this, new PropertyChangedEventArgs( "B" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Blue" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Color" ) );
}
}
}
public Color Color {
get { return this._Color; }
set {
this._Color = value;
if ( this.PropertyChanged != null )
this.AllChanged( );
}
}
public Color Red { get { return Color.FromScRgb( 1.0F, ( float )this.R, 0.0F, 0.0F ); } }
public Color Green { get { return Color.FromScRgb( 1.0F, 0.0F, ( float )this.G, 0.0F ); } }
public Color Blue { get { return Color.FromScRgb( 1.0F, 0.0F, 0.0F, ( float )this.B ); } }
private void AllChanged( ) {
this.PropertyChanged( this, new PropertyChangedEventArgs( "A" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "R" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "G" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "B" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Red" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Green" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Blue" ) );
this.PropertyChanged( this, new PropertyChangedEventArgs( "Color" ) );
}
}
This is the control class :
public partial class ColorDefiner : UserControl {
public static readonly DependencyProperty
_Color = DependencyProperty.Register( "Color", typeof( Color ), typeof( ColorDefiner ) );
public Color Color {
get { return ( Color )this.GetValue( ColorDefiner._Color ); }
set { this.SetValue( ColorDefiner._Color, value ); }
}
private ColorViewModel CVM { get { return this.DataContext as ColorViewModel; } }
public ColorDefiner( ) {
InitializeComponent( );
Binding B = new Binding( "Color" ) { Source = this.DataContext };
this.SetBinding( ColorDefiner._Color, B );
}
}
This is the XAML for the User Control (yes, I did it with a UserControl; this required a data context, and I really don't want to fuss with that yet in a Custom Control - this is really only going to be my own personal control for my own use anyway) :
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:Components="clr-namespace:WPFTools.Components"
xmlns:Controls="clr-namespace:WPFTools.Controls"
x:Class="WPFTools.Controls.ColorDefiner"
mc:Ignorable="d"
Width="100" Height="100" FontFamily="Arial" FontWeight="Bold">
<UserControl.DataContext>
<Controls:ColorViewModel/>
</UserControl.DataContext>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="20"/>
<RowDefinition Height="5"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Viewbox HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<Components:WPFGLabel Text="A" StrokeThickness="0.5" TextAlignment="Right" Stroke="#99000000">
<Components:WPFGLabel.Fill>
<SolidColorBrush Color="{Binding Color}"/>
</Components:WPFGLabel.Fill>
</Components:WPFGLabel>
</Viewbox>
<Viewbox HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Grid.Column="1">
<Components:WPFGLabel Text="R" StrokeThickness="0.5" TextAlignment="Right" Stroke="#99000000">
<Components:WPFGLabel.Fill>
<SolidColorBrush Color="{Binding Red, Mode=OneWay}"/>
</Components:WPFGLabel.Fill>
</Components:WPFGLabel>
</Viewbox>
<Viewbox HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Grid.Column="2">
<Components:WPFGLabel Text="G" StrokeThickness="0.5" TextAlignment="Right" Stroke="#99000000">
<Components:WPFGLabel.Fill>
<SolidColorBrush Color="{Binding Green, Mode=OneWay}"/>
</Components:WPFGLabel.Fill>
</Components:WPFGLabel>
</Viewbox>
<Viewbox HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Grid.Column="3">
<Components:WPFGLabel Text="B" StrokeThickness="0.5" TextAlignment="Right" Stroke="#99000000" RenderTransformOrigin="-7.272,0.575">
<Components:WPFGLabel.Fill>
<SolidColorBrush Color="{Binding Blue, Mode=OneWay}"/>
</Components:WPFGLabel.Fill>
</Components:WPFGLabel>
</Viewbox>
<Viewbox HorizontalAlignment="Stretch" Grid.Row="2" VerticalAlignment="Stretch">
<Slider Orientation="Vertical" TickPlacement="Both" LargeChange="0.1" Maximum="1" SmallChange="0.01" TickFrequency="0.02" Height="90" TabIndex="0" Value="{Binding A, Mode=TwoWay}"/>
</Viewbox>
<Viewbox HorizontalAlignment="Stretch" Grid.Row="2" Grid.Column="1" VerticalAlignment="Stretch">
<Slider Orientation="Vertical" TickPlacement="Both" LargeChange="0.1" Maximum="1" SmallChange="0.01" TickFrequency="0.02" Height="90" TabIndex="1" Value="{Binding R, Mode=TwoWay}"/>
</Viewbox>
<Viewbox HorizontalAlignment="Stretch" Grid.Row="2" Grid.Column="2" VerticalAlignment="Stretch">
<Slider Orientation="Vertical" TickPlacement="Both" LargeChange="0.1" Maximum="1" SmallChange="0.01" TickFrequency="0.02" Height="90" TabIndex="2" Value="{Binding G, Mode=TwoWay}"/>
</Viewbox>
<Viewbox HorizontalAlignment="Stretch" Grid.Row="2" Grid.Column="3" VerticalAlignment="Stretch">
<Slider Orientation="Vertical" TickPlacement="Both" LargeChange="0.1" Maximum="1" SmallChange="0.01" TickFrequency="0.02" Height="90" Value="{Binding B, Mode=TwoWay}"/>
</Viewbox>
</Grid>
</UserControl>
I bound the Brush Color of the Labels to their respective colors in the View Model (A got the entire thing). I Two-Way Bound the value of each slider to it's respective value within the view model, and in the code I bound the Dependency Property to the view model Color property. I tested this, and it worked.
Once again, thank you all for your help.
来源：https://stackoverflow.com/questions/29678176/how-can-i-convert-the-values-of-three-sliders-into-a-color