gridsplitter not behaving as excpected when coupled with scrollviewer and minWidth

Question

I have a grid as background container
this grid contains a scrollviewer so that when I resize the window Up, the content extends with it, but when I resize the window down, the scrollbar appears on the scrollviewer when I reach the minWidth on the sv's content
this scrollviewer contains a grid with two columns
this grid contains one scrollviewer in each column, each one containing in turn a grid.
I have a grid splitter on the first column so that I can resize the columns

disclaimer: I know this is not the optimal way to organize this layout, but this is actually the simplest representation I found to reproduce an issue I have with a much more elaborate layout so please do not offer a solution that would reorganize the layers

here is the xaml :

<Window x:Class="Test.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Text Project">

    <!--background grid-->
    <Grid>

        <ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">

            <!--two columns layout-->
            <Grid MinWidth="600">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>

                <ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
                    <Grid MinWidth="200" Background="Red"/>
                </ScrollViewer>

                <GridSplitter HorizontalAlignment="Right" VerticalAlignment="Stretch" Width="6"/>

                <ScrollViewer Grid.Column="1" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
                    <Grid MinWidth="200" Background="Blue"/>
                </ScrollViewer>
            </Grid>

        </ScrollViewer>

    </Grid>

</Window>

the goal is as follow: - if I resize the window Up, everything scales - if I resize down, when I reach the minWidth, the scroolbars on the topmost scrollviewer appear and its content stops shrinking. (this part works fine) - whatever the topmost scrollviewer's size, I can resize both columns with the gridsplitter - when I reach one column's minwidth, the scrollbar appears on this column's scrollviewer and its content stops shrinking

issue: this second part never happens. What I get is that I can resize until I reach one of the two child grids's minWidth, and then the gridsplitter stops moving, I cannot shrink further and the scrollbars never appear.

I noticed that if I remove the topmost grid and its associated scrollviewer, it works as expected:

<Window x:Class="Test.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Text Project">

            <!--two columns layout-->
            <Grid MinWidth="600">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>

                <ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
                    <Grid MinWidth="200" Background="Red"/>
                </ScrollViewer>

                <GridSplitter HorizontalAlignment="Right" VerticalAlignment="Stretch" Width="6"/>

                <ScrollViewer Grid.Column="1" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
                    <Grid MinWidth="200" Background="Blue"/>
                </ScrollViewer>
            </Grid>

</Window>

I don't understand why the fact that I put the inner grid into a scrollviewer would change the behaviour of the gridsplitter and of the inner scrollviewers, so I anybody knows of a solution, I'd be glad

The outter ScrollViewer give the inner unconstrained width and height so it takes the inner ScrollViewers out of play. Take away the splitter and put a single ScrollViewer in a ScrollViewer - think about it - it makes no sense. — paparazzo
the point of the inner scrollviewer is actually the gridsplitter. Without it I agree that it does not make sense, but What I described (gridsplitter + 2 scrollviewers altogether children of a bigger scrollviewer) seems perfectly valid to me — David
Splitter changes nothing. What is to the left of the splitter unlimited width and what is to the right of the splitter has unlimited width if they are all inside ScrollViewer. Just what does a Scrollview have to horizontal scroll if it has unlimited width? — paparazzo

Eirik Eirik · Accepted Answer · 2013-03-12T11:33:19

Try binding the Width of the two column Grid to the ActualWidth of the outer ScrollViewer, like this:

<!--two columns layout-->
<Grid MinWidth="600" Width="{Binding RelativeSource={RelativeSource AncestorType=ScrollViewer}, Path=ActualWidth}">

gridsplitter not behaving as excpected when coupled with scrollviewer and minWidth

1 Answers