Question

Im new to wpf, and looking for good tutorials to help understand triggers better but im not having much luck. So i thought I would seek some help here. Here is what im trying to do, i have a ScrollViewer that has a stack panel, in the code behind I browse a media folder and added MediaElements to the stackpanel using a foreach loop, what I want to do is when a user hovers over one of these, i want it to glow underneath it, I’m told triggers are the way to go, so here is what i have so far

foreach

                MediaElement newVideoPreview = new MediaElement(); 
                newVideoPreview.Width = 125;
                newVideoPreview.Stretch = Stretch.Uniform; 
                newVideoPreview.Margin = new Thickness(5, 5, 5, 5); 
                newVideoPreview.Volume = 0;

                Trigger trig = new Trigger();
                trig.Property = IsMouseOverProperty;
                trig.Value = true;
                Style style = new Style();
                style.TargetType = newVideoPreview.GetType();
                style.Triggers.Add(trig);
                Setter set  = new Setter();

                OuterGlowBitmapEffect glow = new OuterGlowBitmapEffect();
                glow.GlowColor = Color.FromRgb(0, 0, 205);
                glow.GlowSize = 10;
                set.Value = glow; // <- Crash house
                set.Property = EffectProperty;
                style.Setters.Add(set);
                newVideoPreview.Style = style;

as you can see, i get an invalid argument exception when i try to set the setter.value, im looking for suggestions on how to fix this or do it better, or better tutorials…Thanks for any help

p.s I am using VS2010 beta 2

Update Ive tried this too this dosent work….

<UserControl x:Class="WiiDSUKiosk.WiiFriendlyScrollViewer"
         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" 
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">
<Grid>
    <Grid.Resources>
        <Style TargetType="{x:Type UIElement}">
            <Style.Triggers>
                <Trigger Property="IsMouseOver" Value="true">
                    <Setter Property="BitmapEffect">
                        <Setter.Value>
                            <OuterGlowBitmapEffect GlowColor="Navy" GlowSize="10"/>
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Grid.Resources>
    <ScrollViewer Name="wiiFriendlyScrollViewer" ScrollViewer.HorizontalScrollBarVisibility="Hidden" ScrollViewer.VerticalScrollBarVisibility="Hidden"
                  MouseMove="wiiFriendlyScrollViewer_MouseMove" >

        <StackPanel Name="stackPanelContent" ScrollViewer.HorizontalScrollBarVisibility="Hidden" ScrollViewer.VerticalScrollBarVisibility="Hidden">
        </StackPanel>
    </ScrollViewer>
</Grid>

Answer 1

this is a lot easier to do in xaml, trying to manipulate this stuff in code is a headache.

there is some code in this unrelated article about items control generators that will add the glow when an item is selected in a list box. ( a little more than half way down )

here is the ms example it uses triggers to glow anything that has focus. ( it is a lot easier to understand )