Make tooltip area bigger than the control

Question

I have a chart with thin lines as markers which the user can hover over to get their values.

I would like to make the area in which the tooltip activates bigger but keep the actual line the same size as it is quite difficult for the use to actually hover over.

I also have one line that the user can drag around and it is very difficult to get the precise spot to click and drag.

This is my template for the marker but I am not sure how to accomplish this goal, can anyone point me in the right direction?

<Geometry x:Key="LineGeometry">M 0,0 L 5,0 L 5,15 L 0,15 Z</Geometry>
<DataTemplate>
        <!--  Define the template for the actual markers  -->
        <Path Width="10"
              Height="10"
              HorizontalAlignment="Stretch"
              VerticalAlignment="Stretch"
              Data="{StaticResource LineGeometry}"                 
              Stretch="Fill"
              Stroke="{StaticResource BlackBrush}"
              StrokeThickness="0.5">
            <Path.ToolTip>
              <!-- Lots of tooltip definition stuff -->
            </Path.ToolTip>
        </Path>
 </DataTemplate>

• Visual Studio 2015
• WPF
• C#
• Infragistics XamDataChart

Answer 1

If I understand you correctly, you just want to show tooltip inside your rectangle represented by Path. If so you can just wrap your path in transparent border and set tooltip on border:

    <Border Background="Transparent">
        <Path Width="10"
              Height="10"
              HorizontalAlignment="Stretch"
              VerticalAlignment="Stretch"
              Data="{StaticResource LineGeometry}"
              Stretch="Fill"
              Stroke="Black"
              StrokeThickness="0.5"></Path>
        <Border.ToolTip>
            <TextBlock Text="Tooltip" />
        </Border.ToolTip>
    </Border>

Answer 2

Your actual problem is you have not used the Fill property of Path,so while creating this shape there is literally nothing in between lines, that's why if you check IsMouseOver property when Mouse pointer is inside this shape, it will return false. however if you specify Fill property result will be as expected.

Use Fill property as below and your ToolTip will be visible if Mouse is over Path shape anywhere.:

 Fill="Transparent"

So your output won't get impacted visually. below is a sample program.

XAML:

<Window.Resources>
    <Geometry x:Key="LineGeometry">M 0,0 L 5,0 L 5,15 L 0,15 Z</Geometry>       
</Window.Resources>
<StackPanel>

    <Path Width="100"
              Height="100"
          Name="path"
              HorizontalAlignment="Stretch"
              VerticalAlignment="Stretch"
              Data="{StaticResource LineGeometry}"                 
              Stretch="Fill"
              Stroke="Red" Margin="50"
              StrokeThickness="5"
                Fill="Transparent"
                MouseLeftButtonDown="Path_MouseLeftButtonDown">            
        <Path.ToolTip>
            <TextBlock Text="This is My Tooltip of Path" />
        </Path.ToolTip>
    </Path>

    <StackPanel Orientation="Horizontal">
        <Label Content="Is Mouse Over Path : " />
        <Label Content="{Binding ElementName=path,Path=IsMouseOver}" BorderThickness="0.5" BorderBrush="Black"/>
    </StackPanel>
</StackPanel>

Output:

Sorry,don't know how to captureMousein screenshot, but mouse is in between the shape while image was captured. RemoveFill propertyfromPathand then see the change in ouput.