Question

I have a WPF Form with a such a layout:

<Grid>
    <DataGrid>
    ...
    </DataGrid>
    <Canvas>
    ...contains lines created at runtime...
    </Canvas>
</Grid>

You can see I have a DataGrid where I load files into.
Some of the cells of the Datagrid are getting connected by Lines. These Lines are placed into the canvas. That all works really fine.

But now I have one big problem. I can disable all lines not to go over my whole form by z-index. The only area where they are when I scroll down is the DataGridColumnHeader.

Do you have any idea what i could do that the lines have a lower z-index then my DataGridColumnHeader but a bigger or the same as my DataGridCells?

Answer 1

You cannot solve this problem by means of setting a ZIndex, since this index only controls the z-order of elements inside one Panel.

You can however set the Canvas’s Margin so that it does not cover the DataGridColumnHeader and then set its ClipToBounds property to true.

<Grid> 
    <DataGrid Name="dataGrid"> 
    ... 
    </DataGrid> 
    <Canvas ClipToBounds="True"> 
        <Canvas.Margin>
            <Thickness Top="{Binding ColumnHeaderHeight, ElementName=dataGrid}"/>
        </Canvas.Margin>
    ...contains lines created at runtime... 
    </Canvas> 
</Grid> 

I haven’t tested the XAML above, but it should work.