Gridsplitter: limit row heights to window size

Question

I have just started to experiment with gridsplitters and have stumbled across a very weird behaviour and I cannot seem to fix it. Apparently the others have similar issues (according to google), but there were no helpful comments.

I have a grid with 2 rows. On start up the bottom one has a Hight of 250. The top row takes the rest with *. When I resize the rows with the splitter the behaviour is as expected for the top row. But when I drag the splitter upwards and past the program window, the content of the bottom row will drop out of the window (=move downwards until it is gone). I'd expect that I cannot make each row larger than the parent container.

<Grid x:Name="grid_main" ScrollViewer.VerticalScrollBarVisibility="Disabled" >
    <Grid.RowDefinitions>
        <RowDefinition Height="*"/>
        <RowDefinition MinHeight="250"  Height="250"/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <GridSplitter x:Name="splitter" 
        ResizeDirection="Rows" Grid.Column="0" Grid.ColumnSpan="1" Grid.Row="0" Width="Auto"
        Height="5" HorizontalAlignment="Stretch" VerticalAlignment="Bottom" Margin="0" ResizeBehavior="BasedOnAlignment" />
    <Grid Grid.Column="0" Grid.Row="0">
    </Grid>
    <Grid Grid.Column="0" Grid.Row="1">              
    </Grid>
</Grid>

This is my code. The content of both rows is again hosted in grids and has been removed for the sake of simplicity. Again: Resizing for the top row works fine. But the bottom row can be resized to infinity. It works as expected if I hard-code a MaxHeight. But that has to depend on the window size.

Answer 1

Try changing your second RowDefinition to the following:

<RowDefinition MinHeight="250" MaxHeight="{Binding ElementName=grid_main, Path=ActualHeight}" Height="250"/>

This will ensure that the row height will not exceed the window size.

Answer 2

Richard's solution didn't work for me (the ActualHeight of the grid expanded past the window size along with the row height).

Using Snoop, I found that the ActualHeight of an ancestor ContentPresenter wasn't increasing. Thus the following bottom row definition worked for me, although I was still seeing issues if I set MinHeight on either the top or bottom rows:

<RowDefinition Height="430"
               MaxHeight="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContentPresenter}}, Path=ActualHeight}"/>

Answer 3

This problem only occurs because the second row has an absolute Height. If you actually want an absolute Height value try Richards's solution. Otherwise, just use a relative Height (e.g. 2*) on the second row as well.

Answer 4

Grigory Zhadko's answer is good to me.

I had a problem with this code

gridBase.RowDefinitions[1].Height = (GridLength)gridLengthConverter.ConvertFrom("1");
gridBase.RowDefinitions[3].Height = (GridLength)gridLengthConverter.ConvertFrom("1");

and I fixed it like this

gridBase.RowDefinitions[1].Height = new GridLength(0.1, GridUnitType.Star);
gridBase.RowDefinitions[3].Height = new GridLength(0.1, GridUnitType.Star);

and the grid converter works perfectly