Question

我正在使用windows phone silverlight应用程序，默认的全景模板有一个带有静态gradientstop属性的列表框。

<ListBox ItemsSource="{Binding lbox}" Name="listboxUsers" Margin="2,126,0,6" Grid.Column="1" Grid.ColumnSpan="2" Grid.RowSpan="2">
<SNIP>
    <Rectangle Height="100" Width="100" Margin="12,0,9,0" Name="Recta">
        <Rectangle.Fill>
            <LinearGradientBrush EndPoint="1,0.5" StartPoint="0,0.5">
                <GradientStop Color="Gray" Offset="1"  />
            </LinearGradientBrush>
        </Rectangle.Fill>
      </Rectangle>

我想动态更改gradientstop的color属性，我尝试绑定Color属性：

public class lbox   
{

    public lbox(string par1, string par2, Color par4) 
    { 
        displayname = par1;
        state = par2;  

        gscolor = new GradientStop();
        gscolor.Color = par4;
    }

    public string displayname { get; set; }
    public string state { get; set; }
    public SolidColorBrush lbcolor { get; set; }
    private GradientStop gscolor { get; set; }
}

XAML：

GradientStop Color="{Binding gscolor}" Offset="1"  />

但是，这会导致XMLPaseException：AG_E_PARSER_BAD_PROPERTY_VALUE。我还尝试在后面的代码中使用没有新的Gradientstop实例的颜色属性...请注意，绑定对于字符串值正常工作。

任何人都知道我做错了什么？

修改马特指出我正确的方向：

<Rectangle Height="100" Width="100" Margin="12,0,9,0" Fill="{Binding lbcolor}">

在上面的代码中，lbcolor是SolidColorBrush。

Answer 1

这是不可能的。

在http://blogs.msdn.com/b/nickkramer/archive/2006/08/18/705116.aspx

查看原因

这在http://forums.silverlight.net/forums/p/111477/254754.aspx

进行了深入讨论

Databinding the color of a RadialGradient brush in silverlight 3

的答案有可能解决

Answer 2

您不仅需要将gscolor设置为Color而不是GradientStop。您正在为XAML中的GradientStop对象分配Color。或者，您应该绑定到Color的{{1}}属性。

gscolor

Answer 3

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Animazioni
{
    public partial class MainPage : UserControl
    {
        public Ellipse el = new Ellipse();
        public MainPage()
        {
            InitializeComponent();
            el.Opacity = 0.5;
            el.Height = 100;
            el.Width = 100;

        }

        private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            RadialGradientBrush _rgb = new RadialGradientBrush();
            GradientStop gs1 = new GradientStop();
            GradientStop gs2 = new GradientStop();
            GradientStop gs3 = new GradientStop();

            gs1.Offset = 0;
            gs2.Offset = 0.7;
            gs3.Offset = 1;

            gs1.Color = Colors.Yellow;
            gs2.Color = Colors.Orange;
            gs3.Color = Colors.Red;

           //

            _rgb.GradientStops.Add(gs1);
            _rgb.GradientStops.Add(gs2);
            _rgb.GradientStops.Add(gs3);
            el.Fill = _rgb;

            myCanvas.Children.Add(el);

        }
    }
}

Answer 4

我知道这比我年长，但我遇到了同样的问题。我在DynamicResource中使用了Color，而Storyboard动画正在更改值，因此动态资源丢失了。所以我试图找出如何做到这一点，我最终以编程方式使用Storyboard ColorAnimation。

给定的示例适用于2 GradientStops

xHeader = gradientstops所属的元素。

还有一个静态函数RandomString，它为Storyboard名称生成RandomStrings。

您还可以在那里更改PropertyPath ..

 public void AnimateHeader(Color First, Color Second, Double DurationSecs=0.2)
    {
        Duration duration = new Duration(TimeSpan.FromSeconds(DurationSecs));
        ColorAnimation FirstAnimation = new ColorAnimation();
        ColorAnimation SecondAnimation = new ColorAnimation();

        Storyboard sb = new Storyboard();
        sb.Children.Add(FirstAnimation);
        sb.Children.Add(SecondAnimation);
        FirstAnimation.Duration = duration;
        FirstAnimation.To = First;
        FirstAnimation.RepeatBehavior = new RepeatBehavior(1);
        SecondAnimation.Duration = duration;
        SecondAnimation.To = Second;
        SecondAnimation.RepeatBehavior = new RepeatBehavior(1);
        Storyboard.SetTarget(FirstAnimation, xHeader);
        Storyboard.SetTargetProperty(FirstAnimation, new PropertyPath("Foreground.(GradientBrush.GradientStops)[0].(GradientStop.Color)"));

        Storyboard.SetTarget(SecondAnimation, xHeader);
        Storyboard.SetTargetProperty(SecondAnimation, new PropertyPath("Foreground.(GradientBrush.GradientStops)[1].(GradientStop.Color)"));

        Resources.Add(RandomString(100)+(new DateTime()).Ticks, sb);
        sb.Completed += (o, s) => { Resources.Remove(sb); };
        sb.Begin();
    }

动态改变gradientstop颜色

4 个答案: