Silverlight：“这个名字已存在于树中”

Line:52
Error: Unhandled Error in Silverlight 2 Application
Code: 2028
Category: ParserError
message: The name already exists in the tree: AltLabel.
File:
Line: 0
Position: 0

当我将鼠标悬停在按钮上时,我收到了很多这些消息.对我在这里做错了什么的建议？

干杯

Nik


<UserControl
    xmlns="http://scheR_7_11845@as.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://scheR_7_11845@as.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://scheR_7_11845@as.microsoft.com/expression/blend/2008"
    xmlns:mc="http://scheR_7_11845@as.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    x:Class="SLEntityPresenterWebPart.VerticalTabStop"
    d:DesignWidth="20" d:DesignHeight="27">

    <Grid x:Name="LayoutRoot">
        <StackPanel>
            <Canvas x:Name="TabStopCanvas" Height="27" Width="20">
                <ToolTipservice.ToolTip>
                    <TextBlock x:Name="AltLabel" Text="Substitute me"/>
                </ToolTipservice.ToolTip>
                <Image x:Name="IconImg" Canvas.Left="7" Canvas.Top="9" Width="26" Height="26" source="Contact.png" Canvas.ZIndex="5" Margin="0,-9,0" RenderTransformOrigin="0.5,0.5">
                    <Image.RenderTransform>
                        <TransformGroup>
                            <ScaleTransform ScaleX="0.85" ScaleY="0.85"/>
                            <SkewTransform/>
                            <RotateTransform/>
                            <TranslateTransform X="0"/>
                        </TransformGroup>
                    </Image.RenderTransform>
                </Image>
                <Image source="stop.png" Margin="3,0"/>
            </Canvas>

        </StackPanel>
    </Grid>
</UserControl>