SplineDoubleKeyFrame set from DynamicResource

Question

I want to use a dynamic resource to give the rotate transform angle to a SplineDoubleKeyFrame.  I've used dynamic resources to do this on a doubleAnimation.To

I can set it in code behind if I reference the key by its index, if I do this instead:

            DoubleAnimationUsingKeyFrames 

                daukf=(DoubleAnimationUsingKeyFrames)TryFindResource("thisOne");

            ((SplineDoubleKeyFrame)daukf.KeyFrames[0]).Value = 19;

But this just makes me more curious as to why I can't do that in xaml.

Can anyone tell me why this doesn't work?

thanks

<Window
	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
	xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
	x:Class="UntitledProject1.Window1"
    xmlns:sys="clr-namespace:System;assembly=mscorlib"
	x:Name="Window"
	Title="Window1"
	Width="640" Height="480">
    

	<Window.Resources>
		
        <sys:Double x:Key="sdKey">18.545</sys:Double>

			<DoubleAnimationUsingKeyFrames x:Key="thisOne" 
                   BeginTime="00:00:00" 
                   Storyboard.TargetName="rectangle" 
                   Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[2].(RotateTransform.Angle)">
				<SplineDoubleKeyFrame KeyTime="00:00:0.5" Value="{DynamicResource sdKey}"/>
			</DoubleAnimationUsingKeyFrames>

	</Window.Resources>


	<Grid x:Name="LayoutRoot">
		<Rectangle Fill="#FFB70000" Stroke="#FF000000" 
		HorizontalAlignment="Right" Margin="0,160,232,206" 
		Width="80" RenderTransformOrigin="-3,0" x:Name="rectangle">
			<Rectangle.RenderTransform>
				<TransformGroup>
					<ScaleTransform ScaleX="1" ScaleY="1"/>
					<SkewTransform AngleX="0" AngleY="0"/>
					<RotateTransform Angle="0"/>
					<TranslateTransform X="0" Y="0"/>
				</TransformGroup>
			</Rectangle.RenderTransform>
		</Rectangle>
        
        <Button Height="30" HorizontalAlignment="Right" Margin="0,44,42,0" Name="button1" VerticalAlignment="Top" Width="117" Click="button1_Click">Button</Button>
   
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Windows.Media.Animation;

namespace UntitledProject1
{
	/// <summary>
	/// Interaction logic for Window1.xaml
	/// </summary>
	public partial class Window1 : Window
	{
        Storyboard sb = new Storyboard();

		public Window1()
		{
			this.InitializeComponent();
	
			// Insert code required on object creation below this point.
		}

        private void button1_Click(object sender, RoutedEventArgs e)
        {

             sb.Children.Add((DoubleAnimationUsingKeyFrames)TryFindResource("thisOne"));
            sb.Begin(this, true);


        }
	}
}

Answer 1

Hi Zaurska,

Using DynamicResource markup extensions in XAML equals to setting resource reference in code. For example:
XAML
<TextBlock Name="txtbox" Background="{DynamicResource myBrush}"/>

code behind
this.txtbox.SetResourceReference(TextBlock.BackgroundProperty, "myBrush");

Note that only FrameworkElement or FrameworkContentElement or FrameworkElementFactory class has the SetResourceReference method. That's to say, we can only associate property with a resource on FrameworkElement or FrameworkContentElement or FrameworkElementFactory. The SplineDoubleKeyFrame is not any of above types, so it couldn't be associated with a resource, i.e. using DynamicResource on the SplineDoubleKeyFrame has no effect.

Changing the "DynamicResource" to "StaticResource" in the XAML can solve the problem. For example:

<DoubleAnimationUsingKeyFrames x:Key="thisOne"
                   BeginTime="00:00:00"
                   Storyboard.TargetName="rectangle"
                   Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[2].(RotateTransform.Angle)">
<SplineDoubleKeyFrame KeyTime="00:00:0.5" Value="{StaticResource sdKey}"/>
</DoubleAnimationUsingKeyFrames>


Hope this helps.
If you have any question, please feel free to let me know.

Sincerely,
Linda Liu

---

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Answer 2

thank you,

 I need sdKey to increment at runtime, and the storyboard to respond to that change, if its a Static resource I cant change it, can I? 

In code behind I have done this instead:

                    Double currentAngle =Convert.ToDouble(
                         ((TransformGroup)r.RenderTransform)
                         .Children[2].GetValue(RotateTransform.AngleProperty)
                         .ToString());

                    double d = currentAngle + 18;

                    ((SplineDoubleKeyFrame)daukf.KeyFrames[0]).Value = d;

which does what I need.

I'd still like to do it in Xaml though

Answer 3

Hi Zaurska,

You can bind the Value property of the SplineDoubleKeyFrame to a property of a business class. Change the value of the business class property at run time and the SplineDoubleKeyFrame.Value property will be changed. For example:

<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="UntitledProject1.Window1"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
xmlns:local="clr-namespace:UntitledProject1"
 x:Name="Window"
Title="Window1"
Width="640" Height="480">
   

<Window.Resources>
            <local:MyValueClass x:Key="myvalue" Value="18.545"/>
        
   <DoubleAnimationUsingKeyFrames x:Key="thisOne"
                   BeginTime="00:00:00"
                   Storyboard.TargetName="rectangle"
                   Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[2].(RotateTransform.Angle)">
<SplineDoubleKeyFrame KeyTime="00:00:0.5" Value="{Binding Source={StaticResouce myvalue}, Path=Value}"/>
</DoubleAnimationUsingKeyFrames>

</Window.Resources>

....
</Window>

code behind

  public class MyValueClass:INotifyPropertyChanged
    {
        private double _value;
        public double Value
        {
            get { return _value; }
            set {
                _value = value;
                OnPropertyChanged("Value");               
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        private void OnPropertyChanged(string propname)
        {
            if(PropertyChanged !=null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propname));
            }
        }
    }

the code to change the property value:

private void button1_Click(object sender, RoutedEventArgs e)
{
            (this.Resources["myvalue"] as MyValueClass).Value = 15;
}

Hope this helps.

Sincerely,
Linda Liu

---

Please remember to mark the replies as answers if they help and unmark them if they provide no help.
Welcome to the All-In-One Code Framework! If you have any feedback, please tell us.

Answer 4

even better,

thanks so much!