Question

我创建了一个自定义控件，该控件旨在用作按钮，但具有指定多边形（在按钮内绘制）的点的属性，以及渐变的两种颜色。我已经在代码中声明了所有属性，然后在XAML中编写了模板，但它似乎没有工作。如果我将值硬编码到XAML中它可以正常工作，但如果我通过TemplateBinding使用属性值，似乎没有任何事情发生。关于如何使其发挥作用的任何想法？

这是我的XAML：

<Window x:Class="WPFTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" xmlns:my="clr-namespace:WPFTest">
    <StackPanel>
        <StackPanel.Resources>
            <Style TargetType="my:GradientButton">
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type my:GradientButton}">
                            <Grid>
                                <Ellipse Width="{TemplateBinding Width}" Height="{TemplateBinding Height}" Stroke="{TemplateBinding Foreground}" VerticalAlignment="Top" HorizontalAlignment="Left">
                                    <Ellipse.Fill>
                                        <LinearGradientBrush>
                                            <GradientStop Color="{TemplateBinding GradientStart}" Offset="0"></GradientStop>
                                            <GradientStop Color="{TemplateBinding GradientEnd}" Offset="1"></GradientStop>
                                        </LinearGradientBrush>
                                    </Ellipse.Fill>
                                </Ellipse>
                                <Polygon Points="{TemplateBinding PlayPoints}" Fill="{TemplateBinding Foreground}" />
                            </Grid>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
        </StackPanel.Resources>
        <my:GradientButton Content="Button" Height="50" x:Name="gradientButton1" Width="50" GradientStart="#CCCCCC" GradientEnd="#777777" />
    </StackPanel>
</Window>

这是自定义控件的代码：

public class GradientButton : Button
    {
        internal static DependencyProperty GradientStartProperty;
        internal static DependencyProperty GradientEndProperty;
        internal static DependencyProperty PlayPointsProperty;

        static GradientButton()
        {
            GradientStartProperty = DependencyProperty.Register("GradientStart", typeof(Color), typeof(GradientButton));
            GradientEndProperty = DependencyProperty.Register("GradientEnd", typeof(Color), typeof(GradientButton));
            PlayPointsProperty = DependencyProperty.Register("PlayPoints", typeof(Point[]), typeof(GradientButton));
        }

        public Color GradientStart
        {
            get { return (Color)base.GetValue(GradientStartProperty); }
            set { SetValue(GradientStartProperty, value); }
        }

        public Color GradientEnd
        {
            get { return (Color)base.GetValue(GradientEndProperty); }
            set { SetValue(GradientEndProperty, value); }
        }

        public Point[] PlayPoints
        {
            get //hardcoded return at the moment to get it to work, but this will change later
            {
                System.Collections.Generic.List<Point> result = new System.Collections.Generic.List<Point>();

                double left = this.Width / 2.77;
                double top = this.Height / 4.17;
                double right = this.Width / 1.43;
                double middle = this.Height / 2.0;
                double bottom = this.Height / 1.32;

                result.Add(new Point(left, top));
                result.Add(new Point(right, middle));
                result.Add(new Point(left, bottom));

                return result.ToArray();
            }
            set { SetValue(PlayPointsProperty, value); }
        }
    }

Answer 1

Polygon.Points的类型为PointCollection。我不相信Point[]符合这种类型。您需要更改PlayPoints的类型或使用IValueConverter进行更改类型。

Answer 2

请尝试使用此颜色绑定：

Color="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=GradientStart}"

TemplateBinding仅适用于声明位于ControlTemplate可视树的元素中的有限情况，而LinearGradientBrush则不然。您可以在ControlTemplate中的Trigger Setters中看到相同的行为，并使用相同的修复。

如何在XAML模板中使用WPF自定义控件属性？

2 个答案: