I've spent two straight days on this and still can't figure it out! Please help!
What I want to do seems relatively simple. I have a window with a grid in it. There are three rows: one "Auto", one set to fill remaining space, and one set to "Auto" with a max height. Here is the xaml:
<Grid Name="theGrid" >
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="Auto" MaxHeight="300"></RowDefinition>
</Grid.RowDefinitions>
<ContentControl Grid.Row="0" Content="{Binding fixedLabel}"></ContentControl>
<ContentControl Grid.Row="1" Content="{Binding bigLabel}"></ContentControl>
<ContentControl Grid.Row="2" Content="{Binding gridWithStackPanel}"></ContentControl>
</Grid>
The first two rows just have a simple label in them. The third row is itself made up of a grid. It is a simple grid with two rows, one allowed to fill the remaining space, and one marked "Auto". Here is the xaml for that grid:
<Grid Name="theGrid" Style="{StaticResource BasePGOGridStyle}">
<Grid.RowDefinitions>
<RowDefinition Height="1*"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<ContentControl Grid.Row="0" Content="{Binding stackPanel}"></ContentControl>
<ContentControl Grid.Row="1" Content="{Binding simpleLabel}"></ContentControl>
</Grid>
The desired behavior is simple: the second grid would have a stackpanel as its top item, with a simple label on the bottom. However, if the stackpanel has a lot of items, it just blows out the label on the bottom. Despite being set to "Auto", WPF doesn't seem to reserve the space for the 'simpleLabel'.
What seems to be happening is that WPF tells the second grid "Hey, you are marked down as 'Auto' in your parent grid, so take up as much space as you need". So, the second grid lays itself out as though it has lots of space, showing all of the items in the stackpanel. Then, WPF seems to say, "Wait a sec, there's a maxHeight value for your parent row, so you need to clip yourself". What ends up happening is that the 'simpleLabel' then gets cut out of the layout.
That's my best guess for what's happening, but maybe there is something else going on. I've done extensive research and can't find a solution to the problem. Am I really the only person ever putting a grid within a grid that has a MaxHeight? It seems like a basic part of WPF functionality.
Please let me know if you have any ideas!
Ok, I finally figured out a solution! You have to forget about using maxHeight in the grid row and just place the maxHeight value on the item that you are binding to. This seems to fix the problem completely.
Related
I have an Expander control, and the grid inside will have a ListBox with a Label on top of it saying 'Video Sources'. I am attempting to use Grid Row Definitions to achieve this. My issue however is that the grid rows separate everything evenly. I want the label to be directly on top of the ListBox. Removing the definitons causes the ListBox to fill up the entire grid including covering up the Label (which makes no sense to me as the label is on top).
My current code is below:
<Expander HorizontalAlignment="Left" Height="434" Header="Expander" ExpandDirection="Left" Margin="651,8,0,8">
<Grid Background="#FF252525" ShowGridLines="True">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Label Content="Video Sources" Grid.Row="0"/>
<ListBox Grid.Row="1" d:ItemsSource="{d:SampleData}">
</ListBox>
</Grid>
</Expander>
The code produces this result. You can see there are even gaps between each control. I want the video sources label right above the listbox:
It would be nice if you could set the column name like in a ListView, however as far as I am aware that is not possible. I don't think it's worth using a ListView for something that will only have a single column, either
You have to set the rows height ; to auto (ie: minimal value) and * (ie: remaining space).
Also only two rows definition are needed.
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Label Grid.Row="0"
Content="Video Sources" />
<ListBox Grid.Row="1"
ItemsSource="{d:SampleData}"
VerticalAlignement="Top" />
</Grid>
For reference, this is a chat application. This should give you some idea of a final goal.
Additionally, I am very new to WPF. This is one of my first applications and I am making this as a proof of concept. I've been using Windows Forms up until this point, so any comparison or reference to it would help me understand a bit better.
So, the issue at hand:
The chat box for my chat application is a StackPanel (should it be?) which is programmatically populated with TextBlock elements. I need to find a way to scroll down this StackPanel once the available space runs out. I also need it to automatically scroll to the bottom (like a chat would; you wouldn't be able to see the most recent message otherwise).
The question: How can I make a ScrollViewer properly size dynamically with a StackPanel?
Additionally, I also need this StackPanel to size dynamically as the window is sized. This, in turn, would affect the scroll bar.
My current "solution" is to use a ScrollViewer with the StackPanel nested. However, the ScrollViewer and StackPanel do not size properly with a change in window size, as shown in screenshot #2. The XAML code and a screenshot of the designer is shown below.
<Window x:Name="Main" x:Class="dprCxUiDemoWpf.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:dprCxUiDemoWpf"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Grid Background="#FF171717">
<TextBox x:Name="ChatBox" TextWrapping="Wrap" Background="#FF4F4F4F" Foreground="White" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch" RenderTransformOrigin="-0.118,12.093" Margin="146,0,0,1" VerticalAlignment="Bottom" Height="46" BorderBrush="#FFFF00F3" KeyDown="ChatBox_KeyDown"/>
<Image x:Name="DprLogo" Source="/dprCxUiDemoWpf;component/Images/logo1.png" HorizontalAlignment="Left" Height="60" Margin="10,0,0,10" VerticalAlignment="Bottom" Width="123"/>
<ScrollViewer Background="Red" Height="Auto" Width="Auto" ScrollViewer.CanContentScroll="True" Margin="146,0,0,0" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" VerticalAlignment="Top" MinHeight="372">
<StackPanel x:Name="ChatPanel" Height="Auto" Width="Auto" Background="DimGray" ScrollViewer.CanContentScroll="True" />
</ScrollViewer>
</Grid>
</Window>
(source: gcurtiss.dev)
Please note the following regarding the first screenshot:
A. The black column (containing the logo) is simply the background color of the window; there is nothing there.
B. The gray portion is ChatBox (the StackPanel)
C. The pink highlighted box below is the text box where messages are entered.
I appreciate and accept any and all help!
You have to use the Grid panel properly. You layout its children by defining rows and columns. Grid is a column/row based layout container. Then configure row and column definitions to control the resize behavior of the cells and their content.
Using absolute positioning and sizes will of course prevent controls from responding to their parent's size changes. Most control stretch to fit the available space. But this requires dimension properties being set to Auto.
You said you are "more of a hands-on learner", but you should still read some documentations. Otherwise you will significantly slow down your progress until stagnation.
There are tons of blogs waiting for you to read them. To poke around in the dark will get you nowhere. You need at least to know the basics. Instead of waiting 13+ hours for a copy & paste ready answer, you could have finished multiple tutorials already and solve this on your own. Success is a good feeling. This is a very trivial problem.
Find yourself a good tutorial that you find easy to understand and start to experiment with the Grid after reading it.
According to your posted code, you obviously have zero idea how this panel works and how you can use it to align your controls.
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<ScrollViewer Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2">
<StackPanel />
</ScrollViewer>
<Image Grid.Row="1" Grid.Column="0"
Height="60"
Width="123 />
<TextBox Grid.Row="1" Grid.Column="1" />
</Grid>
I need to find a way to scroll down this StackPanel once the available space runs out. I also need it to automatically scroll to the bottom (like a chat would; you wouldn't be able to see the most recent message otherwise)
You should read about data-binding and MVVM first. Usually you hold an ObservableCollection of items on your VM and bind them to eg a ListBox on your View.
Then you can scroll-down the ListBox, each time a new item got added to your collection:
private void ScrollRecordsListToBottom()
{
if (RecordsList.Items.Count == 0)
return;
var lastItem = RecordsList.Items[RecordsList.Items.Count - 1];
RecordsList.ScrollIntoView(lastItem);
}
I'm currently working on UI for a WPF application, and I want to use a ScrollViewer to show the content that might be out of the viewing area of the screen.
I've read all over the internet in the past 2 days, and from what I understand: the ScrollViewer doesn't have knowledge of it's content's/parent's height unless determined statically; thus if there's no specific height written down (in a case of a StackPanel underneath it for example) it won't allow for scrolling.
Now, let's suppose my UI hierarchy looks like this:
<Window> <!--No height here-->
<Grid>
<StackPanel Orientation="Horizontal"/>
<ContentControl>
<UserControl> <!--This user control doesn't have a specific height or width-->
<Grid>
<ScrollViewer>
<Grid /> <!--This grid doesn't contain any StackPanels, or containers with dynamic height, and this is content I want to show-->
</ScrollViewer>
<Grid />
</Grid>
</UserControl>
</ContentControl>
</Grid>
</Window>
I expected the ScrollViewer to scroll appropriately since there's no dynamic container beneath it, but it didn't, and it appeared that setting a static height to it or to the UserControl above it made it work.
But since the app would work on different screen sizes, and all windows are somehow resize-able, I don't want to write static dimensions.
The solution was to use fractional sizes for the grid (which gives scrollviewer height somehow), example:
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto" /> <!--this gives the second row the space it needs and leaves the scrollviewer with all the remaining space, this will also work if you need to make the second row child fixed-->
</Grid.RowDefinitions>
<ScrollViewer Grid.Row="0"/>
<Grid Grid.Row="1"/>
</Grid>
for a better experience with grids, use WpfAutoGrid.
I have the following scenario:
<ScrollViewer>
<Grid>
<!--many other controls-->
<DataGrid />
</Grid>
</ScrollViewer>
Now, when I bind DataGrid to large amount of data (around 10.000 rows) I am having very slow perfomance. In fact, i get OutOfmemory exception (and I have 8 GB memory)! I read somewhere that this is because ScrollViewer overrides DataGrid virtualisation (or something like that), but I don't know how to prevent that. If I remove the ScrollViewer, problem solved! The data loads in less than a second.
I want to keep the ScrollViewer (because of other controls) and have good performance. Is that possible? If not, is there any other solution-workaround?
A common workaround to these sorts of problems is to add an invisible "sizing element" in the same Row as the DataGrid, then you can bind DataGrid.Height to the ActualHeight of the sizing element. This way, your DataGrid will always consume the Height of the RowDefinition. Example
<ScrollViewer>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Button Content="Some Control.." />
<Rectangle Name="sizingElement"
Grid.Row="1"
Fill="Transparent"
Margin="1"/>
<DataGrid Grid.Row="1"
Height="{Binding ElementName=sizingElement,
Path=ActualHeight, FallbackValue=1}">
<!--...-->
</DataGrid>
<Button Content="Some more controls etc.." Grid.Row="2"/>
</Grid>
</ScrollViewer>
The outer ScrollViewer effectively gives the DataGrid as much space as it likes, that way its height becomes huge, showing all rows at once. Just restrict the DataGrid by explicitly setting a height on it for example.
I'm building a project that loads data from a webservice into a TreeView Control. When the TreeView is contained on the LayoutRoot grid by itself and it's height is set to Auto, if the contents extend beyond the vertical or horizontal limits of the treeview scrollbars appear automatically, as expected.
If that same TreeView control is placed inside a StackPanel, it's behavior changes. When data extends past it's limits, no scrollbar appears and data simply clips off the edge with no access to it. If I manually set the height of the TreeView in this scenario, the scrollbars will appear again as expected.
Clearly there seems to be some interaction between the StackPanel and TreeView that I'm not seeing.
Can anyone explain this and suggest an appropriate way to handle the situation?
Per request in comments:
The following XAML works fine and renders scrollbars as expected (notice the Height on the TreeView is Specified):
<StackPanel >
<controls:TreeView ItemTemplate="{StaticResource MainEntryIndexTemplate}"
x:Name="CodeBookIndexTreeView" Height="500" />
</StackPanel>
The following also displays scrollbars as expected (notice no StackPanel, but the TreeView's Height is set to Auto):
<controls:TreeView ItemTemplate="{StaticResource MainEntryIndexTemplate}"
x:Name="CodeBookIndexTreeView" Height="Auto" />
Finally, this code fails in that the TreeView will not display scrollbars and data scrolls off the bottom and/or right hand side of the control (notice the TreeView is in a StackPanel and the TreeView's Height is set to Auto):
<StackPanel >
<controls:TreeView ItemTemplate="{StaticResource MainEntryIndexTemplate}"
x:Name="CodeBookIndexTreeView" Height="Auto" />
</StackPanel>
Cheers,
Steve
Managed to get this one figured out with some help from the Silverlight.net forums. You can read the original question and answer here. It turns out that a StackPanel oriented vertically (the defaul orientation) will give infinite size to its children, so since the TreeView has infinite size, the scroll bars will never display. This does NOT happen when using a grid as your layout element.
The following XAML will render the TreeView scroll bars as expected. (Notice that the TreeView is contained in row 2 of a Grid, not a StackPanel and that the Height of the TreeView is set to Auto.) There are some additional controls in this code snippet because that was the reason for the extra container in the first place:
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel Orientation="Horizontal" Grid.Row="0">
<TextBlock Text="Enter Search Term" />
<TextBox x:Name="SearchTermTextBox" Width="200" KeyUp="SearchTermTextBox_KeyUp"/>
</StackPanel>
<Button x:Name="SearchButton" Content="Search" Click="SearchButton_Click" Width="100"
HorizontalAlignment="Left" Grid.Row="1" />
<controls:TreeView ItemTemplate="{StaticResource MainEntryIndexTemplate}"
x:Name="CodeBookIndexTreeView" Height="Auto" Grid.Row="2" />
</Grid>
Yeh - StackPanels don't seem to be a great control for containing variable sized objects.
Similarly; I have had trouble with DataTemplates composed of textblocks within a stackpanel, used as ListItem templates within a ListBox. Intention was for the text block to wrap, but instead it just continues beyond the bounds of the list box, for which there is no horizontal scroll. Best I've managed so far was to fix the width of the Grid containing the stackpanels but not yet found a satisfactory solution.. would love to know if there is one!